Materiały źródłowe

• #1 Gastrointestinal Stromal Tumors—Diagnosis and Management: A Brief Review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3096364/

  Gastrointestinal stromal tumors (GISTs) are rare but are the most common mesenchymal tumor in the gastrointestinal tract. They arise from a precursor cell in the myenteric plexus, and most tumors express a characteristic CD117 antigen, which is part of a tyrosine kinase receptor. This finding has led to the development of novel chemotherapeutic agents targeted at these receptors and has revolutionized the treatment of these tumors, which had been historically disappointing. […] The approach to tumors 2 cm in size is more controversial, as these lesions tend to be less aggressive, but the true malignant potential of GISTs can only be determined by surgical resection and histologic evaluation. […] GISTs are often incidentally detected during endoscopic or radiographic studies or during surgery for other conditions.

• #1 Tests for Gastrointestinal Stromal Tumors | American Cancer Society

  https://www.cancer.org/cancer/types/gastrointestinal-stromal-tumor/detection-diagnosis-staging/how-diagnosed.html

  Gastrointestinal stromal tumors (GISTs) are often found because a person is having signs or symptoms. Others are found during exams or tests for other problems. But these symptoms or initial tests arent usually enough to know for sure if a person has a GIST or another type of gastrointestinal (GI) tumor. If a GI tumor is suspected, you will need to have further tests to confirm what it is. […] If a GIST is found, you will likely have further tests to help determine the stage (extent) of the cancer. […] CT scans can be useful in patients who have (or might have) GISTs to find the location and size of a tumor, as well as to see if it has spread to other parts of the body. […] MRI scans can sometimes be useful in people with GISTs to help find the extent of the cancer in the abdomen, but usually CT scans are enough.

• #1 Signs and Symptoms of Gastrointestinal Stromal Tumors | American Cancer Society

  https://www.cancer.org/cancer/types/gastrointestinal-stromal-tumor/detection-diagnosis-staging/signs-symptoms.html

  Most gastrointestinal stromal tumors (GISTs) develop within the wall of the stomach or small intestine. […] GISTs tend to be fragile tumors that can bleed easily. In fact, they are often found because they cause bleeding into the GI tract. […] Other symptoms of GISTs can include: Abdominal (belly) pain, A mass or swelling in the abdomen, Nausea and vomiting, Feeling full after eating only a small amount of food, Loss of appetite, Weight loss, Problems swallowing (for tumors in the esophagus). […] Some tumors grow large enough to block the passage of food through the stomach or intestine. This is called an obstruction, and it can cause severe abdominal pain and vomiting. […] Although many of the possible symptoms of GISTs (like belly pain and nausea) can be caused by things other than cancer, if you have these symptoms, especially if they last for more than a few days, it’s important to see a doctor.

• #1 Gastrointestinal Stromal Tumor (GIST) – Brigham and Women’s Hospital

  https://www.brighamandwomens.org/surgery/surgical-oncology/gastrointestional-stromal-tumor-sarcoma-gist?TRILIBIS_EMULATOR_UA=…%3Fcmp%3Dhrgn%3Fcmp%3Dhrgn%2C%2C%2C%2C%3Fcmp%3Dhrgn%3Fcmp%3Dhrgn

  Gastrointestinal stromal tumors may cause the following symptoms: Abdominal discomfort or pain, Blood in stools, Vomiting, Feeling full after eating only a small amount, Loss of appetite or weight loss, Fatigue due to anemia. […] If you are having symptoms of GIST, your surgeon will ask about your health history, your family’s history of cancer and risk factors. Diagnostic tests may include: Computed tomography scan (CT-scan), Magnetic resonance imaging (MRI), Ultrasound, Colonoscopy, Lower GI (gastrointestinal) series (also called barium enema), Biopsy to look for KIT protein (also called CD117). […] Samples will be taken from the primary tumor, lymph nodes, and other suspicious areas. A pathologist views the tissue under a microscope to look for cancer cells and to find out the grade of the tumor. The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the cells are dividing. High-grade tumors usually grow and spread more quickly than low-grade tumors. […] Pathologists at Dana-Farber Brigham Cancer Center are among the best and most experienced in the world with special expertise in providing an accurate diagnosis for complex cases. In many instances when asked to review a case to provide a second opinion, the diagnosis and treatment plan is changed.

• #1 Gastrointestinal Stromal Tumors (GISTs) Workup: Laboratory Studies, Imaging Studies, Procedures

  https://emedicine.medscape.com/article/278845-workup

  No laboratory test can specifically confirm or rule out the presence of a gastrointestinal stromal tumor (GIST). The following tests are generally ordered in the workup of patients who present with nonspecific abdominal symptoms; abdominal pain; or findings that may be due to complications of GISTs, such as hemorrhage, obstruction, or perforation: […] GISTs are not associated with elevation of any serum tumor markers. However, depending on the location, size, and appearance of the tumor on imaging studies, performing tumor marker assays such as the following for other abdominal neoplasms may be appropriate: […] Imaging studies used in the workup of GISTs include the following: […] CT scanning with intravenous and oral contrast material is a necessary step in the diagnosis and staging of GISTs.

• #1 Gastrointestinal Stromal Tumors—Diagnosis and Management: A Brief Review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3096364/

  Contrast-enhanced computed tomography (CT) (or occasionally magnetic resonance imaging) is the imaging modality of choice to further evaluate an abdominal mass or nonspecific abdominal symptoms. GISTs usually appear as hyperdense enhancing solid mass lesions with IV contrast. […] Ultimately, endoscopic ultrasound is the most accurate method of reaching a specific diagnosis of a subepithelial lesion. […] Because the differential diagnosis of a hypo-echoic submucosal mass arising from the muscularis propria is broad, a definitive diagnosis of GIST can only be made histologically. […] However, EUS-guided fine needle aspiration (EUS-FNA) with a 22-gauge needle or core needle biopsy using a 19-gauge Trucut needle can target the lesion to secure a specimen for cytologic or core tissue examination, respectively.

• #1 Imaging of Gastrointestinal Stromal Tumors: From Diagnosis to Evaluation of Therapeutic Response | Anticancer Research

  https://ar.iiarjournals.org/content/36/6/2639

  Contrast-enhanced CT is the investigation of choice in the imaging algorithm of GIST. […] The presence of an ulcer, mesenteric fat infiltration, direct organ invasion, and metastasis were more frequently observed in gastric GISTs with a high mitotic rate, but no CT feature other than size was found to have any predictive value. […] Contrast-enhanced CT is the most commonly used modality for evaluating response to treatment of GISTs. […] Response evaluation during early stages of targeted therapy is crucial in order to optimize treatment and prevent unnecessary delays, toxicity and costs. […] Thus, RECIST criteria might not be a reliable indicator for monitoring metastatic GISTs, especially in the early stage of imatinib treatment. […] PET has been found to be highly sensitive in detecting early response, and to be useful in predicting long-term response to imatinib in patients with metastatic GIST.

• #1 Gastrointestinal stromal tumor – Knowledge @ AMBOSS

  https://www.amboss.com/us/knowledge/gastrointestinal-stromal-tumor/

  Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the GI tract, which are rare overall. […] Initial evaluation typically involves imaging studies (e.g., abdominal ultrasound or CT with contrast). Definitive diagnosis is made by a multidisciplinary team at specialized GIST centers and includes core biopsy. […] Refer all patients with suspected GIST to a multidisciplinary team at a specialized reference center for GISTs. […] Initial studies include ultrasound: hypoechogenic lesions that may displace surrounding structures and/or intra-abdominal metastases, and CT abdomen (with contrast): mass with clearly defined borders, possibly heterogeneous contrast enhancement. […] Specialized studies include endoscopy or endoscopic ultrasound: esophageal, gastric, or duodenal GISTs, core biopsy: molecular genetic testing for CD117 (c-KIT) or PDGFRA mutations and immunohistochemistry, MRI: assessment of rectal GISTs, and CT chest, abdomen, and pelvis with contrast: staging.

• #1 Tests for Gastrointestinal Stromal Tumors | American Cancer Society

  https://www.cancer.org/cancer/types/gastrointestinal-stromal-tumor/detection-diagnosis-staging/how-diagnosed.html

  PET scans can also be helpful in finding out if a drug treatment is working, as they can often give an answer quicker than CT or MRI scans. […] GISTs are often below the surface (mucosa) of the inner lining of the GI tract. This can make them harder to see with endoscopy than more common GI tract tumors, which typically start in the mucosa. […] If the tumor has broken through the inner lining of the GI tract and is easy to see on endoscopy, there is a greater chance that the GIST might spread to other parts of the body. […] Even if something abnormal is seen on an imaging test such as a barium x-ray or CT scan, these tests often can’t tell for sure if the abnormal area is a GIST, some other type of tumor (benign or cancer), or some other condition (like an infection). The only way to know what it is for sure is to remove cells from the area. This procedure is called a biopsy.

• #1 Gastrointestinal stromal tumor | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/gastrointestinal-stromal-tumor-2?lang=us

  Surgical en-bloc resection is the primary mode of therapy for GISTs. Up to 50% of all GISTs will have evidence of metastatic disease at the time of presentation, which significantly impacts prognosis. […] Adjuvant chemotherapy with imatinib is effective in the majority of cases and has had a dramatic impact on prognosis even with only one year of therapy, reducing recurrence at one year from 17% to 3%. […] Fluorine-18 FDG PET-CT may be used in monitoring treatment response and is considered superior to CT in monitoring treatment response in the initial phases of treatment.

• #1 Gastrointestinal stromal tumors: a comprehensive review – Parab – Journal of Gastrointestinal Oncology

  https://jgo.amegroups.org/article/view/23883/19709

  Many classification systems have evolved over the years but none have proved to be superior to the other. In 2002, Fletcher and colleagues collaborated to create the NIH classification, the first GIST classification system. […] The gold standard of treatment for GISTs is surgical resection through laparoscopy, however if the patient is unstable then an open laparotomy is the preferred method of treatment. […] The 3 agents approved for the treatment of GISTs are imatinib (Gleevec), sunitinib (Sutent), and ponatinib. […] In addition to surgery and targeted therapy, it is important that patients who fall into the high-risk categories for metastasis follow-up with serial CT scans every three months for five years. […] GISTs are best identified by CT scan but also can be seen on abdominal ultrasound, MRI, and PET. The pathology of GISTs consist of either spindle cells, epithelioid cells, or mixed cell types. GISTs most commonly stain positive for CD117 and DOG-1.

• #1 Gastrointestinal Stromal Tumors (GISTs): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/278845-overview

  Gastrointestinal stromal tumors (GISTs) account for less than 1% of GI tumors, but they are the most common mesenchymal neoplasms of the GI tract. […] No laboratory test can specifically confirm or rule out the presence of a GIST. The following tests are generally ordered in the workup of patients who present with nonspecific abdominal symptoms; abdominal pain; or complications such as hemorrhage, obstruction, or perforation: […] Imaging studies […] Computed tomography scans of the abdomen and pelvis: […] Essential for the diagnosis and staging of GISTs […] Endoscopy: […] Frequently performed early in the workup of patients with GI bleeding, abdominal pain, or GI obstructive symptoms from GISTs […] EUS characteristics of malignant GISTs include the following: […] Biopsy provides definitive diagnosis

• #1 Gastrointestinal Stromal Tumors—Diagnosis and Management: A Brief Review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3096364/

  The general consensus is that essentially all GISTs have malignant potential. […] CT or endosonographic features of increased malignancy risk include tumor size exceeding 3 cm and irregular margins. […] In addition to size and mitotic count, anatomic location of the tumor factors into risk stratification. […] A recent guideline publication by the National Comprehensive Cancer Network suggests that all localized, nonmetastatic GISTs 2 cm in size should be resected. […] The management of smaller GISTs (2 cm) is more controversial. […] Prior to 2001, complete resection of primary GISTs was not possible in approximately 50% of patients, resulting in a median survival of only 1 to 2 years. […] Treatment of these tumors was revolutionized, however, by the subsequent finding that mutational activation of KIT or PDGFRA stimulated their growth.

• #1 Current clinical management of gastrointestinal stromal tumor

  https://www.wjgnet.com/1007-9327/full/v24/i26/2806.htm

  GISTs should be diagnosed by immunohistochemical analysis including assessment of KIT, CD34, and/or discovered on gastrointestinal stromal tumor 1 (DOG1). However, it is more difficult to obtain a conclusive histologic diagnosis of a GIST than gastrointestinal cancer by standard endoscopic forceps biopsy because a GIST is covered by normal mucosa. […] At present, EUS-guided fine needle aspiration (EUS-FNA) is the most accurate, safe, and reliable preoperative immunohistological test to secure a definitive diagnosis of SELs. Aggressive use of EUS and EUS-FNA for SELs is the key to facilitating early intervention of GISTs. […] GISTs have no specific endoscopic or EUS findings, and diagnosis is difficult to achieve by histopathological examination using hematoxylin and eosin staining alone. Immunohistochemical analysis such as that involving KIT, CD34, or DOG1 measurement is essential for a definitive diagnosis.

• #1 GASTROINTESTINAL STROMAL TUMORS – touchONCOLOGY

  https://touchoncology.com/gastrointestinal-cancers/journal-articles/gastrointestinal-stromal-tumors-gist-paving-the-way-for-modern-oncology-epidemiology-diagnosis-treatment/

  If biopsy is required, endoscopic ultrasound guided fine needle aspiration (EUS-FNA) biopsy is an acceptable option and can be a safe and reliable way to obtain the diagnosis and is associated with a lower risk for seeding or potential spread of disease. […] In a study of 65 patients, EUS-FNA had a sensitivity of 82 % and a specificity of 100 %. […] Another method of biopsy that can be used is endoscopic ultrasound-guided trucut biopsy. […] Immunohistochemistry of GIST […] In recent years, IHC staining for KIT expression (CD117) has become integral to the diagnosis of GIST, nearly 90 % of which harbor activating mutations in the KIT receptor tyrosine kinase gene. […] Approximately 95 % of GIST are positive for the CD117 antigen by IHC staining. […] The staining pattern may be cytoplasmic, membranous, and/or paranuclear (Golgi pattern).

• #1 Gastrointestinal Stromal Tumors Treatment (PDQ®) – NCI

  https://www.cancer.gov/types/soft-tissue-sarcoma/hp/gist-treatment-pdq

  GISTs should be included in the differential diagnosis of any intra-abdominal nonepithelial malignancy. Standard diagnostic interventions may include: Computed tomography (CT), Magnetic resonance imaging (MRI), Positron emission tomography (PET), Endoscopy. […] Endoscopic ultrasound with fine-needle aspiration (FNA) biopsy is useful in the diagnosis of GISTs in the upper GI tract, as most tumors arise below the mucosal layer and grow in an endophytic fashion. Endoscopic ultrasound-guided FNA biopsy is preferred to percutaneous biopsy, given the risk of tumor hemorrhage and peritoneal dissemination. […] GISTs range in size from less than 1 cm to more than 40 cm, with an average size of approximately 5 cm when diagnosed clinically. […] The clinical presentation of patients with GISTs varies depending on the following: Anatomical location, Tumor size, Rate of tumor growth.

• #1 Tests for Gastrointestinal Stromal Tumors | American Cancer Society

  https://www.cancer.org/cancer/types/gastrointestinal-stromal-tumor/detection-diagnosis-staging/how-diagnosed.html

  Not everyone who has a tumor that might be a GIST needs a biopsy before treatment. If the doctor suspects a tumor is a GIST, a biopsy is usually done only if it will help determine treatment options. […] If GIST is suspected, some of the proteins most often tested for are KIT (also known as CD117) and DOG1. Most GIST cells have these proteins, but cells of most other types of cancer do not, so tests for these proteins can help tell whether a GI tumor is a GIST or not. […] Testing might also be done to look for mutations in the KIT or PDGFRA genes, as most GIST cells have mutations in one or the other.

• #1 Gastrointestinal stromal tumor – Wikipedia

  https://en.wikipedia.org/wiki/Gastrointestinal_stromal_tumor

  Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs arise in the smooth muscle pacemaker interstitial cell of Cajal, or similar cells. They are defined as tumors whose behavior is driven by mutations in the KIT gene (85%), PDGFRA gene (10%), or BRAF kinase (rare). 95% of GISTs stain positively for KIT (CD117). Most (66%) occur in the stomach and gastric GISTs have a lower malignant potential than tumors found elsewhere in the GI tract. […] The definitive diagnosis is made with a biopsy, which can be obtained endoscopically, percutaneously with CT or ultrasound guidance or at the time of surgery. A biopsy sample will be investigated under the microscope by a pathologist physician. The pathologist examines the histopathology to identify the characteristics of GISTs (spindle cells in 70-80%, epitheloid aspect in 20-30%).

• #1

  https://www.gistsupport.org/about-gist/diagnosis-pathology-results/

  The pathologist examines the appearance, shape, and features (morphology and histology) of tumor cells under the microscope to narrow the possibilities. The pathologist selects and applies immunohistochemical tests to tumor samples. These tests involve using antibodies to detect the presence of proteins that are expressed by the tumor cells. The pattern of proteins that are present or missing in a respective tumor in conjunction with the histomorphology of the tissue is taken into account for the final diagnosis. […] Therefore, a positive result for KIT antibody testing is a strong indication of a GIST diagnosis. […] Another immunohistochemical marker often found to be positive in GIST is CD34, a protein normally expressed by hematopoietic precursor cells (stem cells that generate new blood cells) and some interstitial cells of Cajal.

• #1 The standard diagnosis, treatment, and follow-up of gastrointestinal stromal tumors based on guidelines

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4688306/

  Although gastrointestinal stromal tumors (GISTs) are a rare type of cancer, they are the commonest sarcoma in the gastrointestinal tract. […] Many GIST guidelines have been published to guide the diagnosis and treatment of the disease. […] This review describes the current standard diagnosis, treatment, and follow-up of GISTs based on the recommendations of several guidelines and expert consensus. […] It is suggested that diagnosis and treatment based on the guidelines will improve the prognosis of patients and the quality of medical care, as well as control medical costs. […] The pathological diagnosis of GIST depends on the morphology and immunohistochemical findings. […] KIT positivity is a major defining feature for the diagnosis of GIST for a tumor that has morphological features compatible with GIST, although KIT positivity alone is not sufficient for the diagnosis.

• #1 Gastrointestinal stromal tumor – Wikipedia

  https://en.wikipedia.org/wiki/Gastrointestinal_stromal_tumor

  When GIST is suspected as opposed to other causes for similar tumors the pathologist can use immunohistochemistry (specific antibodies that stain the molecule CD117 [also known as c-KIT]). 95% of all GISTs are CD117-positive. […] If the CD117 stain is negative and suspicion remains that the tumor is a GIST, the newer antibody DOG1 can be used. Also, sequencing of KIT and PDGFRA can be used to prove the diagnosis. […] The purpose of radiologic imaging is to locate the lesion, evaluate for signs of invasion and detect metastasis. […] Preferred imaging modalities in the evaluation of GISTs are CT and MRI, and, in selected situations, endoscopic ultrasound. CT advantages include its ability to demonstrate evidence of nearby organ invasion, ascites, and metastases. […] Malignancy is characterized by local invasion and metastases, usually to the liver, omentum and peritoneum. However, cases of metastases to bone, pleura, lungs and retroperitoneum have been seen.

• #1 Clinical Diagnosis of Gastrointestinal Stromal Tumor (GIST): From the Molecular Genetic Point of View

  https://www.mdpi.com/2072-6694/11/5/679

  Before the identification of CD117 expression in GISTs, CD34 was considered the best marker for GIST, but it was neither sensitive (only for two-thirds of GISTs) nor specific (immunoreactive in fibroblastic and endothelial cell tumors). […] The findings of KIT and ICCs, c-KIT proto-oncogene mutations and CD117 expression were identified in most GISTs, which opened a new era of molecular diagnosis in GISTs. […] Although CD117 is a sensitively and specifically expressed marker in GISTs, CD117 is not universally expressed in all GISTs; however, it can be expressed in other tumors, such as melanomas, adenoid cystic carcinomas, Merkel cell carcinomas, Kaposi sarcomas, liposarcomas or even leiomyosarcomas (rarely). […] Therefore, additional markers are needed to compensate for the weakness of CD117. A novel marker, DOG1 (Discovered On GIST-1), was first discovered in 2004 and is widely used in most pathology laboratories.

• #1 Clinical Diagnosis of Gastrointestinal Stromal Tumor (GIST): From the Molecular Genetic Point of View

  https://www.mdpi.com/2072-6694/11/5/679

  In conclusion, DOG1 showed similar and compatible sensitivity and specificity with CD117, and both can compensate for the weakness and limitations in the diagnosis of GIST. The combination of both CD117 and DOG1 in an IHC panel covers more than 98% of GISTs in clinical practice. […] Although either CD117 or DOG1 can be detected in non-GIST tumors, appropriate clinical and pathological assessments in combination with CD117/DOG1 are important for correctly diagnosing GIST.

• #1 Gastrointestinal Stromal Tumors (GISTs) – Gastrointestinal Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gastrointestinal-disorders/tumors-of-the-gastrointestinal-tract/gastrointestinal-stromal-tumors-gists

  Gastrointestinal stromal tumors are tumors of the gastrointestinal tract derived from mesenchymal precursor cells in the gut wall (interstitial cells of Cajal). Diagnosis is usually by endoscopy. […] Diagnosis of GISTs is usually by endoscopy, with biopsy and endoscopic ultrasonography for staging. […] Immunohistochemistry with positive staining for CD117 (C-KIT) and DOG-1 are pathognomonic for the diagnosis of GIST. […] Once diagnosed, all patients require complete staging with CT of the chest, abdomen, and pelvis.

• #1

  https://journals.lww.com/cancerjournal/fulltext/2017/13060/diagnosis_and_management_of_gastrointestinal.2.aspx

  Immunohistologic features of GISTs differentiate it from other mesenchymal tumors such as leiomyomas, schwannomas, leiomyoblastomas, and leiomyosarcomas. […] Other important markers used in the diagnosis of GISTs include CD34, vimentin, keratin, smooth muscle actin (SMA), and S100. […] The National Comprehensive Cancer Network (NCCN) reported the proportion of positivity of GISTs toward various markers as KIT (95%), CD34 (60-70%), SMA (40%), S-100 (5%), desmin (12%), and keratin (12%). […] The effectiveness experienced in unresectable GISTs led their use in both preoperative and adjuvant therapy. Preoperative treatment with imatinib improves the resectability by reducing the size of the tumors (neoadjuvant therapy) which were initially inoperable. […] Although GIST is not common, it represents the majority of the GI mesenchymal neoplasms. Risk stratification is crucial in the management and outcomes of the disease. Surgical resection remains as the gold standard in the treatment. Complete resection is related to the postoperative survival in patients.

• #1 Gastrointestinal Stromal Tumors Treatment (PDQ®) – NCI

  https://www.cancer.gov/types/soft-tissue-sarcoma/hp/gist-treatment-pdq

  For patients with GISTs characterized by a PDGFRA D842V variant, avapritinib is used as first-line therapy, given the high clinical benefit and imatinib-resistance in this subtype. […] The primary treatment of patients with metastatic or recurrent GISTs involves medical therapy with a TKI. […] Therapy with imatinib is the standard first-line treatment for most patients with metastatic or recurrent disease. […] Neoadjuvant imatinib may be used for patients with very large primary GISTs or poorly positioned small GISTs (considered unresectable without the risk of significant morbidity or functional deficit, such as needing a formal gastrectomy, pancreatectomy, or other major organ resection) until surgical therapy is feasible. […] The management of patients with gastrointestinal stromal tumors (GISTs) is a multidisciplinary effort involving close collaboration between pathologists, medical oncologists, surgeons, and imaging experts.

• #1 Gastrointestinal Stromal Tumors (GISTs) | Choose the Right Test

  https://arupconsult.com/content/gastrointestinal-stromal-tumors

  KIT and PDGFRA mutational analysis is strongly recommended during the initial diagnostic evaluation and should always be performed before beginning treatment. […] The identification of GISTs with genotyping is important because of the availability of specific, molecular-targeted therapy with KIT or PDGFRA TKIs, such as imatinib or, in the case of imatinib-resistant GIST, sunitinib. […] Approximately 10-15% of GISTs lack mutations in the KIT or PDGFRA genes and are referred to as wild-type GISTs. […] Tumors that lack KIT or PDGFRA mutations should be considered for further mutational analysis, including BRAF and SDH gene mutation testing. […] GISTs may range from completely benign to aggressively malignant. Prognosis and malignant potential of GISTs are partially assessed by size and mitotic rate of the tumor. Most gastric GISTs are indolent, and those that are 2 cm are considered to be of low risk, whereas micro-GISTs (1 cm) are invariably benign. However, it is difficult to predict the behavior of GISTs based on pathologic features alone; therefore, tumor site is also important to consider. GISTs in the small intestine or colorectum tend to be more aggressive than gastric GISTs. […] The mutational status of KIT and PDGFRA is not used to determine malignant potential. These mutations may be found in benign, indolent tumors and aggressive, high-grade tumors.

• #1 The standard diagnosis, treatment, and follow-up of gastrointestinal stromal tumors based on guidelines

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4688306/

  Mutation testing, at least for the KIT and PDGFRA genes, is recommended when TKIs, such as imatinib, sunitinib, and regorafenib, are to be used. […] A mutation analysis may add prognostic information for GIST patients, especially for some specific subtypes, and genotyping can provide critical biomarkers to predict the activity of TKIs. […] Most GISTs are detected by endoscopy as a submucosal tumor (SMT), and the pathological diagnosis is often made after surgery. […] The objectives of follow-up after complete surgery may be early detection and treatment of relapses. […] All the clinical practice guidelines contain a follow-up policy based on expert consensus.

• #1 Gastrointestinal Stromal Tumors (GISTs) | Choose the Right Test

  https://arupconsult.com/content/gastrointestinal-stromal-tumors

  Gastrointestinal (GI) stromal tumors (GISTs) account for less than 1% of all GI tumors, yet are still the most common mesenchymal tumors of the GI tract. The diagnosis of GIST is based on histologic examination. Further ancillary testing, including immunohistochemical staining and mutational analysis, provides confirmation of diagnosis and prognostic information and delivers therapeutic implications. […] The National Comprehensive Cancer Network (NCCN) and European Society for Medical Oncology (ESMO) consider mutational analysis standard practice and strongly encourage including it in the diagnostic workup for all GISTS. […] Histologic examination by a pathologist is the gold standard for the diagnosis of GIST. The pathologist will direct the diagnostic workup and perform ancillary testing, such as immunohistochemical staining for KIT (CD117) or DOG1, and KIT and PDGFRA mutational analysis.

• #1 Gastrointestinal Stromal Tumors (GISTs) Workup: Laboratory Studies, Imaging Studies, Procedures

  https://emedicine.medscape.com/article/278845-workup

  Gastric GISTs greater than 10 cm but with a mitotic index of 5/50 HPF or less have only a 12% risk of progressive disease, compared with 34-52% risk of progressive disease in the other tumor locations. […] Many studies have shown that tumor diameter greater than 5 cm is associated with increased risk for malignancy. However, the relation of size to malignant potential may be gradual, with no clear cut-off point.

• #1 Pathology Outlines – Gastrointestinal stromal tumor (GIST)

  https://www.pathologyoutlines.com/topic/softtissueGIST.html

  Gastrointestinal stromal tumor (GIST) is a mesenchymal neoplasm with variable behavior, characterized by differentiation toward the interstitial cells of Cajal based on IHC and molecular studies (Gastroenterol Clin North Am 2013;42:399) […] Diagnosis of GIST is commonly initiated through nonspecific symptoms such as abdominal pain, gastrointestinal bleeding or obstruction (Ther Adv Med Oncol 2023;15:17588359231192388) […] Tissue sampling is the gold standard for a definitive diagnosis […] Abdominal computerized tomography (CT) scan with contrast and image acquisitions of the arterial and portal phases is the first choice to study location and extension (Ther Adv Med Oncol 2023;15:17588359231192388) […] Pathology report must include information for risk assessment (anatomical location, tumor size, mitotic activity) and other important prognostic factors, such as tumor rupture and margin status

• #1 Gastrointestinal Stromal Tumors (GISTs) Workup: Laboratory Studies, Imaging Studies, Procedures

  https://emedicine.medscape.com/article/278845-workup

  MRI can be an especially helpful adjunct to CT in the evaluation of large tumors that have necrotic and hemorrhagic components. […] Endoscopy is frequently performed early in the workup of patients with GISTs, to evaluate GI bleeding, abdominal pain, or GI obstructive symptoms. […] While the diagnosis can often be made using ultrasonography-guided biopsy, the use of biopsy is controversial in an otherwise primary, resectable lesion suspicious for GIST. […] CD117 plays an important role in the latest specific diagnostic criteria for GISTs. […] Positive CD117 staining in a spindle-shaped cell GI tumor is diagnostic for GIST, as depicted in the image below. […] No consensus has been reached regarding a uniform staging system, and none of the currently used classifications is fully satisfactory. Most staging systems employ the American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) classification, which utilizes the three most important survival predictors: tumor size, histologic grade, and presence or absence of distant metastatic disease.

• #1 Gastrointestinal stromal tumor – Wikipedia

  https://en.wikipedia.org/wiki/Gastrointestinal_stromal_tumor

  For localized, resectable adult GISTs, if anatomically and physiologically feasible, surgery is the primary treatment of choice. Surgery can be potentially curative, but watchful waiting may be considered in small tumors in carefully selected situations. […] A substantial proportion of GIST tumors have a high risk of recurrence, as estimated by a number of validated risk stratification schemes, and can be considered for adjuvant therapy.

• #1 Gastrointestinal Stromal Tumors—Diagnosis and Management: A Brief Review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3096364/

  Patients who are intolerant or resistant to imatinib may respond to sunitinib malate (Sutent), which is also an oral tyrosine kinase inhibitor that is less specific than imatinib. […] In addition to primary therapy for unresectable and metastatic disease, imatinib mesylate is also recommended as neoadjuvant therapy for both large tumors and poorly positioned small GISTs that may be considered marginally resectable on technical grounds. […] For primary localized resectable GISTs, standard of care is surgery followed by postoperative radiologic surveillance. […] Several large studies have recently been launched to evaluate the efficacy of adjuvant imatinib for tumor recurrence.

• #1 GASTROINTESTINAL STROMAL TUMORS – touchONCOLOGY

  https://touchoncology.com/gastrointestinal-cancers/journal-articles/gastrointestinal-stromal-tumors-gist-paving-the-way-for-modern-oncology-epidemiology-diagnosis-treatment/

  Although KIT positivity is a major defining feature of GIST, it is no longer an absolute requirement; KIT expression is a constitutional feature and not a consequence of the mutation. […] For patients with unresectable or metastatic disease, treatment with imatinib is associated with significant improvements in OS from 18 to 57 months. […] In patients with metastatic disease responding to imatinib, complete metastasectomy if feasible can allow for possible long-term survival; however, debulking surgery with R2 resection is not beneficial. […] Other locoregional treatments such as RFA or hepatic artery embolization with or without chemotherapy may achieve long-lasting disease control and may be considered in highly selected patients. […] In patients with primary or secondary resistance to imatinib, second-line treatment with sunitinib or third-line therapy with regorafenib is recommended; imatinib dose escalation is a viable option.

• #1 Gastrointestinal Stromal Tumor (GIST)

  https://my.clevelandclinic.org/health/diseases/17031-gist-cancer-information

  Your oncologist will monitor your recovery and overall health even after you finish treatment. You may have follow-up appointments every three to six months. […] Survival rates vary depending on tumor size and activity at the time of diagnosis, your overall health and the tumors response to treatment. Overall, data from the U.S. National Cancer Institute (NCI) show that 85% of people with GIST were alive five years after diagnosis. […] If you have questions about what to expect, ask your oncologist to explain survival rates and what the data mean for you.

• #1 Current clinical management of gastrointestinal stromal tumor

  https://www.wjgnet.com/1007-9327/full/v24/i26/2806.htm

  The principle treatment strategy for immunohistologically confirmed GISTs is as follows: (1) Surgical resection is the first choice for resectable GISTs without metastasis; and (2) Administration of tyrosine kinase inhibitors such as imatinib is the primary approach for unresectable, metastatic, or recurrent GISTs. […] Early diagnosis (early GISTs without metastasis) with early surgical resection is the only promising way to obtain complete cure of this disease.

• #1 Imaging of Gastrointestinal Stromal Tumors: From Diagnosis to Evaluation of Therapeutic Response | Anticancer Research

  https://ar.iiarjournals.org/content/36/6/2639

  Imaging may help in the early diagnosis of imatinib-related complications, such as bleeding into the gastrointestinal tract or intratumoral sites and fluid retention: pleural effusion, pulmonary edema, and ascites. […] Imaging provides valuable information on detection, characterization, staging and prediction of treatment response of GISTs, contributing to optimization of patient management in all phases of treatment.

• #2 Gastrointestinal stromal tumor – Wikipedia

  https://en.wikipedia.org/wiki/Gastrointestinal_stromal_tumor

  Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs arise in the smooth muscle pacemaker interstitial cell of Cajal, or similar cells. They are defined as tumors whose behavior is driven by mutations in the KIT gene (85%), PDGFRA gene (10%), or BRAF kinase (rare). 95% of GISTs stain positively for KIT (CD117). Most (66%) occur in the stomach and gastric GISTs have a lower malignant potential than tumors found elsewhere in the GI tract. […] The definitive diagnosis is made with a biopsy, which can be obtained endoscopically, percutaneously with CT or ultrasound guidance or at the time of surgery. A biopsy sample will be investigated under the microscope by a pathologist physician. The pathologist examines the histopathology to identify the characteristics of GISTs (spindle cells in 70-80%, epitheloid aspect in 20-30%).

• #2 Signs and Symptoms of Gastrointestinal Stromal Tumors | American Cancer Society

  https://www.cancer.org/cancer/types/gastrointestinal-stromal-tumor/detection-diagnosis-staging/signs-symptoms.html

  Most gastrointestinal stromal tumors (GISTs) develop within the wall of the stomach or small intestine. […] GISTs tend to be fragile tumors that can bleed easily. In fact, they are often found because they cause bleeding into the GI tract. […] Other symptoms of GISTs can include: Abdominal (belly) pain, A mass or swelling in the abdomen, Nausea and vomiting, Feeling full after eating only a small amount of food, Loss of appetite, Weight loss, Problems swallowing (for tumors in the esophagus). […] Some tumors grow large enough to block the passage of food through the stomach or intestine. This is called an obstruction, and it can cause severe abdominal pain and vomiting. […] Although many of the possible symptoms of GISTs (like belly pain and nausea) can be caused by things other than cancer, if you have these symptoms, especially if they last for more than a few days, it’s important to see a doctor.

• #2 Gastrointestinal Stromal Tumors Treatment (PDQ®) – NCI

  https://www.cancer.gov/types/soft-tissue-sarcoma/hp/gist-treatment-pdq

  The signs and symptoms of GISTs include: GI bleeding (most common presentation), which may be acute (melena or hematemesis) or chronic, resulting in anemia, Acute tumor rupture, GI obstruction, Pain, Dysphagia, Early satiety. […] GISTs can occur anywhere along the GI tract, but most often are found in the stomach or small intestine. […] GISTs should be included in the differential diagnosis of any intra-abdominal nonepithelial malignancy. […] GISTs are composed of spindle cells (70%), epithelioid cells (20%), or mixed spindle and epithelioid cells (10%). […] Approximately 85% of GISTs contain oncogenic variants in one of two receptor tyrosine kinases (RTKs): KIT, PDGFRA. […] Approximately 95% of GISTs are positive for the CD117 antigen, an epitope of KIT RTK expressed by ICC. […] The TKI imatinib mesylate is used as first-line therapy for most patients with KIT- and PDGFRA-variant GISTs.

• #2 Gastrointestinal stromal tumor (GIST) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/gastrointestinal-stromal-tumors/cdc-20387715

  A gastrointestinal stromal tumor, also called a GIST, is a type of cancer that begins in the digestive system. GISTs happen most often in the stomach and small intestine. […] A GIST starts when nerve cells in the digestive system develop changes in their DNA. A cell’s DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time. In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to grow and multiply quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells. […] Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.

• #2 Gastrointestinal Stromal Tumors—Diagnosis and Management: A Brief Review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3096364/

  Contrast-enhanced computed tomography (CT) (or occasionally magnetic resonance imaging) is the imaging modality of choice to further evaluate an abdominal mass or nonspecific abdominal symptoms. GISTs usually appear as hyperdense enhancing solid mass lesions with IV contrast. […] Ultimately, endoscopic ultrasound is the most accurate method of reaching a specific diagnosis of a subepithelial lesion. […] Because the differential diagnosis of a hypo-echoic submucosal mass arising from the muscularis propria is broad, a definitive diagnosis of GIST can only be made histologically. […] However, EUS-guided fine needle aspiration (EUS-FNA) with a 22-gauge needle or core needle biopsy using a 19-gauge Trucut needle can target the lesion to secure a specimen for cytologic or core tissue examination, respectively.

• #2 Imaging of Gastrointestinal Stromal Tumors: From Diagnosis to Evaluation of Therapeutic Response | Anticancer Research

  https://ar.iiarjournals.org/content/36/6/2639

  Once considered an obscure tumor entity with poor prognosis, gastrointestinal stromal tumors (GISTs) are nowadays recognized as the most common mesenchymal tumors of the alimentary tract. […] This review highlights the role of imaging in the detection, characterization, preoperative staging, postoperative assessment, therapy-response evaluation and treatment-related toxicities. All this information is crucial in optimizing patient management. […] Contrast-enhanced computed tomography is the most commonly used modality for staging the disease and assessing treatment response, whereas positron-emission tomography adds valuable functional information. […] The clinical diagnosis is mainly based on imaging, as biopsy runs the risk of tumor rupture or seeding of the biopsy tract, in otherwise resectable disease.

• #2 Gastrointestinal Stromal Tumors (GISTs) Workup: Laboratory Studies, Imaging Studies, Procedures

  https://emedicine.medscape.com/article/278845-workup

  MRI can be an especially helpful adjunct to CT in the evaluation of large tumors that have necrotic and hemorrhagic components. […] Endoscopy is frequently performed early in the workup of patients with GISTs, to evaluate GI bleeding, abdominal pain, or GI obstructive symptoms. […] While the diagnosis can often be made using ultrasonography-guided biopsy, the use of biopsy is controversial in an otherwise primary, resectable lesion suspicious for GIST. […] CD117 plays an important role in the latest specific diagnostic criteria for GISTs. […] Positive CD117 staining in a spindle-shaped cell GI tumor is diagnostic for GIST, as depicted in the image below. […] No consensus has been reached regarding a uniform staging system, and none of the currently used classifications is fully satisfactory. Most staging systems employ the American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) classification, which utilizes the three most important survival predictors: tumor size, histologic grade, and presence or absence of distant metastatic disease.

• #2 Imaging of Gastrointestinal Stromal Tumors: From Diagnosis to Evaluation of Therapeutic Response | Anticancer Research

  https://ar.iiarjournals.org/content/36/6/2639

  Contrast-enhanced CT is the investigation of choice in the imaging algorithm of GIST. […] The presence of an ulcer, mesenteric fat infiltration, direct organ invasion, and metastasis were more frequently observed in gastric GISTs with a high mitotic rate, but no CT feature other than size was found to have any predictive value. […] Contrast-enhanced CT is the most commonly used modality for evaluating response to treatment of GISTs. […] Response evaluation during early stages of targeted therapy is crucial in order to optimize treatment and prevent unnecessary delays, toxicity and costs. […] Thus, RECIST criteria might not be a reliable indicator for monitoring metastatic GISTs, especially in the early stage of imatinib treatment. […] PET has been found to be highly sensitive in detecting early response, and to be useful in predicting long-term response to imatinib in patients with metastatic GIST.

• #2 Gastrointestinal Stromal Tumors (GISTs): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/278845-overview

  Gastrointestinal stromal tumors (GISTs) account for less than 1% of GI tumors, but they are the most common mesenchymal neoplasms of the GI tract. […] No laboratory test can specifically confirm or rule out the presence of a GIST. The following tests are generally ordered in the workup of patients who present with nonspecific abdominal symptoms; abdominal pain; or complications such as hemorrhage, obstruction, or perforation: […] Imaging studies […] Computed tomography scans of the abdomen and pelvis: […] Essential for the diagnosis and staging of GISTs […] Endoscopy: […] Frequently performed early in the workup of patients with GI bleeding, abdominal pain, or GI obstructive symptoms from GISTs […] EUS characteristics of malignant GISTs include the following: […] Biopsy provides definitive diagnosis

• #2 Gastrointestinal stromal tumor (GIST) – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/gastrointestinal-stromal-tumors/diagnosis-treatment/drc-20579539

  To diagnose a gastrointestinal stromal tumor, your healthcare professional might start by asking you about your symptoms and your health. This cancer, which also is called a GIST, happens in the digestive system. […] If symptoms suggest that you may have a GIST, you might need other tests to find the cancer. These tests may include: […] Imaging tests help your healthcare team find your tumor and see its size. Tests might include ultrasound, CT, MRI and positron emission tomography (PET) scans. Not everyone needs every test. […] This test uses a long, thin tube (endoscope) with a light on the end. The tube goes through the mouth and down the throat. This test looks at the inside of the esophagus, stomach and the first part of the small intestine. […] This test also uses an endoscope, but with an ultrasound probe on the tip of the scope. The ultrasound probe uses sound waves to make pictures of the tumor and show its size.

• #2 Endoscopic Ultrasound Advanced Techniques for Diagnosis of Gastrointestinal Stromal Tumours

  https://www.mdpi.com/2072-6694/15/4/1285

  Endoscopic ultrasound is now regarded as a valuable technique for assessing subepithelial lesions and determining their potential malignancy. […] Gastrointestinal Stromal Tumors (GISTs) are subepithelial lesions (SELs) that commonly develop in the gastrointestinal tract. GISTs, unlike other SELs, can exhibit malignant behavior, so differential diagnosis is critical to the decision-making process. Endoscopic ultrasound (EUS) is considered the most accurate imaging method for diagnosing and differentiating SELs in the gastrointestinal tract by assessing the lesions precisely and evaluating their malignant risk. […] The diagnosis of a GIST relies on typical cell morphology (spindle cells) and immunohistochemistry, with strong reactivity for receptor tyrosine kinase KIT or CD34. Additional tests include DOG1 staining or mutation search of the KIT or PDGFRA genes.

• #2 Gastrointestinal stromal tumor of the stomach: How to manage?

  https://www.wjgnet.com/1948-5190/full/v2/i8/271.htm

  EUS-FNA should be performed for all hypoechoic solid tumors imaged by EUS. […] The reported accuracy of preoperative diagnosis of EUS-FNA using immunohistochemical analysis for surgically resected GIST cases ranges from 91% to 100%. The diagnostic accuracy of EUS-FNA using immunohistochemical analysis is excellent. The reported diagnostic rate for tumors less than 2 cm, 2 cm to 4cm, and 4cm or more was 71%, 86%, and 100%, respectively. This accurate preoperative histological proof of GIST using EUS-FNA facilitates the surgeons and oncologists decision, making for early local resection and early start of imatinib treatment. […] EUS-FNA is a safe and accurate test in the diagnosis of GIST. At present, aggressive use of EUS-FNA is the only viable way of allowing early diagnosis and early treatment of this disease from the point of view of the endoscopist.

• #2 GASTROINTESTINAL STROMAL TUMORS – touchONCOLOGY

  https://touchoncology.com/gastrointestinal-cancers/journal-articles/gastrointestinal-stromal-tumors-gist-paving-the-way-for-modern-oncology-epidemiology-diagnosis-treatment/

  Gastrointestinal stromal tumors (GIST) are relatively rare tumors arising in the gastrointestinal tract. […] The diagnosis of GIST has been fraught with difficulty and they have often been misdiagnosed as leiomyoma, leiomysarcoma, neurofibroma, or benign/borderline malignant potential tumors. […] The identification of the specific expression of the KIT protein (CD117) as a reliable phenotypic marker of GIST has led to a re-appraisal and re-evaluation of pathologic diagnosis and has provided more concrete information. […] Preoperative pathologic diagnosis usually is not required if imaging is consistent with a GIST, the tumor is resectable without significant morbidity, and the patient is an operative candidate. […] In cases where operative morbidity is high or the diagnosis is unclear, biopsy may be warranted.

• #2 The standard diagnosis, treatment, and follow-up of gastrointestinal stromal tumors based on guidelines

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4688306/

  Although gastrointestinal stromal tumors (GISTs) are a rare type of cancer, they are the commonest sarcoma in the gastrointestinal tract. […] Many GIST guidelines have been published to guide the diagnosis and treatment of the disease. […] This review describes the current standard diagnosis, treatment, and follow-up of GISTs based on the recommendations of several guidelines and expert consensus. […] It is suggested that diagnosis and treatment based on the guidelines will improve the prognosis of patients and the quality of medical care, as well as control medical costs. […] The pathological diagnosis of GIST depends on the morphology and immunohistochemical findings. […] KIT positivity is a major defining feature for the diagnosis of GIST for a tumor that has morphological features compatible with GIST, although KIT positivity alone is not sufficient for the diagnosis.

• #2 Differential diagnosis of gastrointestinal stromal tumors versus leiomyomas by special stains | BMC Gastroenterology | Full Text

  https://bmcgastroenterol.biomedcentral.com/articles/10.1186/s12876-024-03511-5

  The objective of the study was to investigate whether special stains can differentiate gastrointestinal stromal tumors (GISTs) and gastrointestinal leiomyomas (GILs). […] GISTs were often associated with a higher risk of malignancy. […] In this study, the gender, age of onset, size and sites of the lesions, together with the number of mucosal or lamina propria lesions all have significant differences, nevertheless, there was no significant difference in cell morphology of GISTs and GILs tested by hematoxylin eosin (HE) stain, and all showed low echo areas by EUS examination. […] In this retrospective study, the GISTs and GILs had been diagnosed by immunohistochemistry combined with clinical morphology. […] In conclusion, MT and AB-PAS stains could also identify GISTs and GILs cases, particularly, AB-PAS was more sensitive and more specific, providing a more cost-effective, simple, and high sensitivity and specificity inspection methods, which should be noticed and widely used in the future, especially in resource-limited grass-roots testing institution or in cases with inconclusive immunostains or insufficient material.

• #2 Clinical Diagnosis of Gastrointestinal Stromal Tumor (GIST): From the Molecular Genetic Point of View

  https://www.mdpi.com/2072-6694/11/5/679

  Clinical Diagnosis of Gastrointestinal Stromal Tumor (GIST): From the Molecular Genetic Point of View […] Gastrointestinal stromal tumors (GISTs) originating from the interstitial cells of Cajal are mesenchymal tumors of the gastrointestinal tract and have been found to harbor c-KIT mutations and KIT (CD117) expression since 1998. […] Twenty years after the discovery of KIT in GISTs, the diagnosis of GISTs became much more accurate by using immunohistochemical (IHC) panel (CD117/DOG1) and molecular analysis (KIT/PDGFRA), both of which constitute the gold standard of diagnosis in GISTs. The accurately molecular diagnosis of GISTs guides clinicians to precision medicine and provides optimal treatment for the patients with GISTs. […] Therefore, it is crucial to make an accurate diagnosis of GISTs so that optimal treatment can be used for patients with GISTs. Here, we discuss the diagnostic development in GISTs, focusing on protein expression by IHC and genetic alterations.

• #2 Gastrointestinal stromal tumor – Wikipedia

  https://en.wikipedia.org/wiki/Gastrointestinal_stromal_tumor

  When GIST is suspected as opposed to other causes for similar tumors the pathologist can use immunohistochemistry (specific antibodies that stain the molecule CD117 [also known as c-KIT]). 95% of all GISTs are CD117-positive. […] If the CD117 stain is negative and suspicion remains that the tumor is a GIST, the newer antibody DOG1 can be used. Also, sequencing of KIT and PDGFRA can be used to prove the diagnosis. […] The purpose of radiologic imaging is to locate the lesion, evaluate for signs of invasion and detect metastasis. […] Preferred imaging modalities in the evaluation of GISTs are CT and MRI, and, in selected situations, endoscopic ultrasound. CT advantages include its ability to demonstrate evidence of nearby organ invasion, ascites, and metastases. […] Malignancy is characterized by local invasion and metastases, usually to the liver, omentum and peritoneum. However, cases of metastases to bone, pleura, lungs and retroperitoneum have been seen.

• #2

  https://www.gistsupport.org/about-gist/diagnosis-pathology-results/

  The pathologist examines the appearance, shape, and features (morphology and histology) of tumor cells under the microscope to narrow the possibilities. The pathologist selects and applies immunohistochemical tests to tumor samples. These tests involve using antibodies to detect the presence of proteins that are expressed by the tumor cells. The pattern of proteins that are present or missing in a respective tumor in conjunction with the histomorphology of the tissue is taken into account for the final diagnosis. […] Therefore, a positive result for KIT antibody testing is a strong indication of a GIST diagnosis. […] Another immunohistochemical marker often found to be positive in GIST is CD34, a protein normally expressed by hematopoietic precursor cells (stem cells that generate new blood cells) and some interstitial cells of Cajal.

• #2

  https://journals.lww.com/cancerjournal/fulltext/2017/13060/diagnosis_and_management_of_gastrointestinal.2.aspx

  Immunohistologic features of GISTs differentiate it from other mesenchymal tumors such as leiomyomas, schwannomas, leiomyoblastomas, and leiomyosarcomas. […] Other important markers used in the diagnosis of GISTs include CD34, vimentin, keratin, smooth muscle actin (SMA), and S100. […] The National Comprehensive Cancer Network (NCCN) reported the proportion of positivity of GISTs toward various markers as KIT (95%), CD34 (60-70%), SMA (40%), S-100 (5%), desmin (12%), and keratin (12%). […] The effectiveness experienced in unresectable GISTs led their use in both preoperative and adjuvant therapy. Preoperative treatment with imatinib improves the resectability by reducing the size of the tumors (neoadjuvant therapy) which were initially inoperable. […] Although GIST is not common, it represents the majority of the GI mesenchymal neoplasms. Risk stratification is crucial in the management and outcomes of the disease. Surgical resection remains as the gold standard in the treatment. Complete resection is related to the postoperative survival in patients.

• #2 The standard diagnosis, treatment, and follow-up of gastrointestinal stromal tumors based on guidelines

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4688306/

  Mutation testing, at least for the KIT and PDGFRA genes, is recommended when TKIs, such as imatinib, sunitinib, and regorafenib, are to be used. […] A mutation analysis may add prognostic information for GIST patients, especially for some specific subtypes, and genotyping can provide critical biomarkers to predict the activity of TKIs. […] Most GISTs are detected by endoscopy as a submucosal tumor (SMT), and the pathological diagnosis is often made after surgery. […] The objectives of follow-up after complete surgery may be early detection and treatment of relapses. […] All the clinical practice guidelines contain a follow-up policy based on expert consensus.

• #2 Gastrointestinal stromal tumour (GIST): British Sarcoma Group clinical practice guidelines | British Journal of Cancer

  https://www.nature.com/articles/s41416-024-02672-0

  For KIT/PDGFRA WT GISTs which are not NF1-related, IHC for succinate dehydrogenase B (SDHB) should be performed if available since loss of expression may assist the diagnosis and may help guide therapy. Further molecular analysis may demonstrate a loss of functional variant in a SDH gene or epigenetic loss, usually in SDHC. […] Patients with high risk of recurrence or distant relapse should receive 3 years of adjuvant imatinib, provided their tumour is not likely to be resistant to therapy. The most effective treatment currently available for PDGFRA D842V-mutant GIST is avapritinib. It is not currently approved by NICE.

• #2 Gastrointestinal stromal tumour (GIST): British Sarcoma Group clinical practice guidelines | British Journal of Cancer

  https://www.nature.com/articles/s41416-024-02672-0

  Molecular analysis has predictive value for sensitivity to molecular-targeted therapy, and prognostic value. The inclusion of KIT/PDGFRA molecular analysis in the diagnostic work-up of all GISTs is highly recommended but as a minimum, such analysis should be performed on all the following specimens: resected moderate or high-risk GISTs at any site; resected GISTs showing tumour rupture; biopsies diagnostic of GIST prior to neoadjuvant or adjuvant therapy; specimens from patients with unresectable and/or metastatic GIST; GISTs which are suspected to be syndromic. […] The diagnosis of GIST should be established by a pathologist experienced in the disease and should include the use of IHC and, if necessary, molecular analysis (which should be performed by an accredited laboratory). If initial treatment with imatinib is planned, it is essential to confirm the diagnosis of GIST, since there is a wide differential. It may be necessary to perform a percutaneous core needle biopsy if the tumour is inaccessible to EUS biopsy.

• #2 Gastrointestinal Stromal Tumors (GISTs) | Choose the Right Test

  https://arupconsult.com/content/gastrointestinal-stromal-tumors

  KIT/PDGFRA mutational assessment is important for decision-making and treatment purposes, given that gastrointestinal (GI) stromal tumors (GISTs) have a variety of subtypes with different predictive and prognostic relevance. […] Current therapeutic strategies for GISTs revolve around targeted therapy against PDGFRA, KIT, and related receptor tyrosine kinases. […] Mutational profiling, for example, can identify mutations that are associated with imatinib resistance, such as PDGFRA D842V, wild-type GIST, and KIT exon 9 mutations that confer partial imatinib resistance; tumors with these mutations may respond to higher doses of imatinib. […] Individuals with a GI tract mass suspected to be GIST should undergo biopsy and histologic examination. The results of immunohistochemical staining and mutational analysis may aid the clinician in determining the most appropriate course of action based on the most recent therapeutic guidelines put forth by the National Institutes of Health/National Cancer Institute and other major health organizations.

• #2 Gastrointestinal Stromal Tumors (GISTs) Workup: Laboratory Studies, Imaging Studies, Procedures

  https://emedicine.medscape.com/article/278845-workup

  Gastric GISTs greater than 10 cm but with a mitotic index of 5/50 HPF or less have only a 12% risk of progressive disease, compared with 34-52% risk of progressive disease in the other tumor locations. […] Many studies have shown that tumor diameter greater than 5 cm is associated with increased risk for malignancy. However, the relation of size to malignant potential may be gradual, with no clear cut-off point.

• #2 Diagnostic and prognostic markers for gastrointestinal stromal tumors in Norway | Modern Pathology

  https://www.nature.com/articles/3800976

  In GISTs, tumor size and mitotic activity are the most consistent clinicopathological features indicative of aggressive clinical behavior, features not readily assessable from typical bite or core biopsies. […] Here we have studied the immunohistochemical stainings for the proposed biomarkers p16 and L1 in GISTs to see if they can aid in the clinical prognostic assessment. […] Our results validate the established clinical prognostic markers, but do not validate the prognostic values of p16 and L1 immunohistochemical biomarkers presented in other series.

• #2 Gastrointestinal Stromal Tumor: Diagnosis and Management

  https://clinmedjournals.org/articles/ijsrp/international-journal-of-surgery-research-and-practice-ijsrp-6-093.php?jid=ijsrp

  All tumors were treated surgically and were entirely resectable with R0 resection in 29 subjects and R1 resection in one subject. […] Imatinib (400 mg/day) treatment was initiated postoperatively in 12 patients (7 intermediate risk patients and five high-risk patients). […] The relationship between the mitotic index and disease-free survival is shown in Figure 4. Statistically, the mitotic index increased and the disease-free survival decreased. […] In this report, disease-free survival was associated with the AFIP-Miettinen classification. According to the AFIP-Miettinen classification, the disease-free survival rate decreased as the risk or progression increased. […] Successful management of GISTs is complete surgical resection and adjuvant imatinib therapy for intermediate and high-risk patients. […] In this study, the mitotic index and tumor size were found to be statistically significant regarding prognosis. […] For recurrent and metastatic GISTs, targeted, personalized therapy is highly recommended, and consideration for further surgery should be based on individual need.

• #2 Gastrointestinal Stromal Tumors (GISTs) | Choose the Right Test

  https://arupconsult.com/content/gastrointestinal-stromal-tumors

  KIT and PDGFRA mutational analysis is strongly recommended during the initial diagnostic evaluation and should always be performed before beginning treatment. […] The identification of GISTs with genotyping is important because of the availability of specific, molecular-targeted therapy with KIT or PDGFRA TKIs, such as imatinib or, in the case of imatinib-resistant GIST, sunitinib. […] Approximately 10-15% of GISTs lack mutations in the KIT or PDGFRA genes and are referred to as wild-type GISTs. […] Tumors that lack KIT or PDGFRA mutations should be considered for further mutational analysis, including BRAF and SDH gene mutation testing. […] GISTs may range from completely benign to aggressively malignant. Prognosis and malignant potential of GISTs are partially assessed by size and mitotic rate of the tumor. Most gastric GISTs are indolent, and those that are 2 cm are considered to be of low risk, whereas micro-GISTs (1 cm) are invariably benign. However, it is difficult to predict the behavior of GISTs based on pathologic features alone; therefore, tumor site is also important to consider. GISTs in the small intestine or colorectum tend to be more aggressive than gastric GISTs. […] The mutational status of KIT and PDGFRA is not used to determine malignant potential. These mutations may be found in benign, indolent tumors and aggressive, high-grade tumors.

• #2 Diagnostic and prognostic markers for gastrointestinal stromal tumors in Norway | Modern Pathology

  https://www.nature.com/articles/3800976

  A total of 91 to 98% of GISTs stain positively for KIT (CD117), which is a major factor in the initial identification of GIST and therefore is often the inclusion criterion into many reported series. […] Prognostic factors in GISTs are controversial, but the most accepted pathologic features are mitotic rate and tumor size. […] An evidence-based approach for defining the risk of aggressive behaviour in GISTs, based on tumor size and mitotic count, has been presented in a consensus document from multiple scientists in the field. […] Tissue microarrays are useful for rapid testing of the diagnostic and prognostic utility of antibodies in large numbers of archival samples. […] The purpose of this study was to validate the clinical and immunohistochemical prognostic markers on a large series of defined GISTs from Norway.

• #2 Imaging of Gastrointestinal Stromal Tumors: From Diagnosis to Evaluation of Therapeutic Response | Anticancer Research

  https://ar.iiarjournals.org/content/36/6/2639

  Imaging may help in the early diagnosis of imatinib-related complications, such as bleeding into the gastrointestinal tract or intratumoral sites and fluid retention: pleural effusion, pulmonary edema, and ascites. […] Imaging provides valuable information on detection, characterization, staging and prediction of treatment response of GISTs, contributing to optimization of patient management in all phases of treatment.

• #2 Gastrointestinal stromal tumours (GISTs) | Canadian Cancer Society

  https://cancer.ca/en/cancer-information/cancer-types/soft-tissue-sarcoma/what-is-soft-tissue-sarcoma/types-of-soft-tissue-sarcoma/gists

  GISTs are different than other types of soft tissue sarcoma, so they are treated differently. When deciding which treatments to offer for a GIST, your healthcare team will consider: where the GIST is in the body; if its a low-risk or high-risk GIST; if surgery can be done (its resectable) or not (its unresectable); types of gene mutations in the GIST; your overall health; what you prefer or want. […] You may be offered one or more of the following treatments for a GIST. […] Surgery is the main treatment for GISTs that haven’t spread (metastasized). The cancer is removed along with some normal tissue around it (called a complete resection). Depending on the size of the tumour and where it is in the GI tract, you may have one of the following surgeries: Wedge or segmental resection removes a section of the stomach containing a small GIST; Gastrectomy removes part or all of the stomach through a cut (incision) in the abdomen. It is done for GISTs in the stomach; Bowel resection removes part of the small intestine or large intestine or both; En bloc resection removes the tumour and surrounding areas as one piece. It is used for GISTs that are attached to nearby organs.

• #2 Current clinical management of gastrointestinal stromal tumor

  https://www.wjgnet.com/1007-9327/full/v24/i26/2806.htm

  The principle treatment strategy for immunohistologically confirmed GISTs is as follows: (1) Surgical resection is the first choice for resectable GISTs without metastasis; and (2) Administration of tyrosine kinase inhibitors such as imatinib is the primary approach for unresectable, metastatic, or recurrent GISTs. […] Early diagnosis (early GISTs without metastasis) with early surgical resection is the only promising way to obtain complete cure of this disease.

• #2 Gastrointestinal Stromal Tumors (GISTs): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/278845-overview

  See Workup for more detail. […] The discovery in 2000 that the tyrosine kinase inhibitor (TKI) imatinib, initially used to treat chronic myeloid leukemia, is effective in treating metastatic GISTs revolutionized the care of patients with GISTs. […] The FDA has also approved the newer tyrosine kinase inhibitors sunitinib and regorafenib for treatment of GISTs that are unresponsive to imatinib.

• #2 Gastrointestinal Stromal Tumors Treatment (PDQ®) – NCI

  https://www.cancer.gov/types/soft-tissue-sarcoma/hp/gist-treatment-pdq

  For patients with GISTs characterized by a PDGFRA D842V variant, avapritinib is used as first-line therapy, given the high clinical benefit and imatinib-resistance in this subtype. […] The primary treatment of patients with metastatic or recurrent GISTs involves medical therapy with a TKI. […] Therapy with imatinib is the standard first-line treatment for most patients with metastatic or recurrent disease. […] Neoadjuvant imatinib may be used for patients with very large primary GISTs or poorly positioned small GISTs (considered unresectable without the risk of significant morbidity or functional deficit, such as needing a formal gastrectomy, pancreatectomy, or other major organ resection) until surgical therapy is feasible. […] The management of patients with gastrointestinal stromal tumors (GISTs) is a multidisciplinary effort involving close collaboration between pathologists, medical oncologists, surgeons, and imaging experts.

• #2

  https://www.gistsupport.org/about-gist/diagnosis-pathology-results/

  Pathologists usually apply several other tests to identify the presence of markers indicating cell differentiation toward smooth-muscle or neural characteristics. […] If the tumor is KIT-negative, then the pattern of results for these other markers will indicate if a non-GIST diagnosis is likely. […] It is important to make the correct diagnosis to choose the correct treatment options.

• #3 Gastrointestinal Stromal Tumors (GISTs): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/278845-overview

  Gastrointestinal stromal tumors (GISTs) account for less than 1% of GI tumors, but they are the most common mesenchymal neoplasms of the GI tract. […] No laboratory test can specifically confirm or rule out the presence of a GIST. The following tests are generally ordered in the workup of patients who present with nonspecific abdominal symptoms; abdominal pain; or complications such as hemorrhage, obstruction, or perforation: […] Imaging studies […] Computed tomography scans of the abdomen and pelvis: […] Essential for the diagnosis and staging of GISTs […] Endoscopy: […] Frequently performed early in the workup of patients with GI bleeding, abdominal pain, or GI obstructive symptoms from GISTs […] EUS characteristics of malignant GISTs include the following: […] Biopsy provides definitive diagnosis

• #3 Current clinical management of gastrointestinal stromal tumor

  https://www.wjgnet.com/1007-9327/full/v24/i26/2806.htm

  Gastrointestinal stromal tumors (GISTs) are the most common malignant subepithelial lesions (SELs) of the gastrointestinal tract. They originate from the interstitial cells of Cajal located within the muscle layer and are characterized by over-expression of the tyrosine kinase receptor KIT. Pathologically, diagnosis of a GIST relies on morphology and immunohistochemistry [KIT and/or discovered on gastrointestinal stromal tumor 1 (DOG1) is generally positive]. The prognosis of this disease is associated with the tumor size and mitotic index. The standard treatment of a GIST without metastasis is surgical resection. A GIST with metastasis is usually only treated by tyrosine kinase inhibitors without radical cure; thus, early diagnosis is the only way to improve its prognosis. […] However, a GIST is usually detected as a SEL during endoscopy, and many benign and malignant conditions may manifest as SELs. Conventional endoscopic biopsy is difficult for tumors without ulceration. Most SELs have therefore been managed without a histological diagnosis. However, a favorable prognosis of a GIST is associated with early histological diagnosis and R0 resection. Endoscopic ultrasonography (EUS) and EUS-guided fine needle aspiration (EUS-FNA) are critical for an accurate diagnosis of SELs. EUS-FNA is safe and effective in enabling an early histological diagnosis and adequate treatment. This review outlines the current evidence for the diagnosis and management of GISTs, with an emphasis on early management of small SELs.

• #3 GASTROINTESTINAL STROMAL TUMORS – touchONCOLOGY

  https://touchoncology.com/gastrointestinal-cancers/journal-articles/gastrointestinal-stromal-tumors-gist-paving-the-way-for-modern-oncology-epidemiology-diagnosis-treatment/

  If biopsy is required, endoscopic ultrasound guided fine needle aspiration (EUS-FNA) biopsy is an acceptable option and can be a safe and reliable way to obtain the diagnosis and is associated with a lower risk for seeding or potential spread of disease. […] In a study of 65 patients, EUS-FNA had a sensitivity of 82 % and a specificity of 100 %. […] Another method of biopsy that can be used is endoscopic ultrasound-guided trucut biopsy. […] Immunohistochemistry of GIST […] In recent years, IHC staining for KIT expression (CD117) has become integral to the diagnosis of GIST, nearly 90 % of which harbor activating mutations in the KIT receptor tyrosine kinase gene. […] Approximately 95 % of GIST are positive for the CD117 antigen by IHC staining. […] The staining pattern may be cytoplasmic, membranous, and/or paranuclear (Golgi pattern).

• #3 Gastrointestinal stromal tumors: a comprehensive review – Parab – Journal of Gastrointestinal Oncology

  https://jgo.amegroups.org/article/view/23883/19709

  Gastrointestinal stromal tumors (GISTs) are rare neoplasms of the gastrointestinal tract associated with high rates of malignant transformation. Most GISTs present asymptomatically. They are best identified by computed tomography (CT) scan and most stain positive for CD117 (C-Kit), CD34, and/or DOG-1. […] GISTs can be identified on abdominal ultrasound, CT scan, magnetic resonance imaging (MRI), and positron emission transverse tomography (PET). CT enterography is the best modality to use to identify location of these tumors, any perforation, invasion of these tumors into nearby structures, or metastasis. […] The diagnosis of GISTs are made with histopathology and immunochemistry. GISTs have three different histologic findings, including spindle (70%), epithelioid (20%), or mixed type (10%).

• #3 Diagnostic and prognostic markers for gastrointestinal stromal tumors in Norway | Modern Pathology

  https://www.nature.com/articles/3800976

  Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tract. The diagnosis of GIST is based on histology together with a panel of immunohistochemical markers; the most important is KIT (CD117). […] A total of 434 cases of GISTs were confirmed by histology and immunohistochemistry, and incorporated into tissue microarrays. […] High mitotic rate, large tumor size, nuclear atypia, and small bowel primary site were all validated as negative prognostic factors in GISTs. […] Expression of p16 was significantly correlated with unfavorable prognosis, whereas L1 expression was not. […] The diagnosis of GIST is often suspected histologically, but such tumors can have a broad morphologic spectrum. A panel of immunohistochemical markers is used to aid in correct diagnosis.

• #3 GIST Diagnosis – The Life Raft Group

  https://liferaftgroup.org/gist-diagnosis/

  Using this technique, the pathologist applies various antibodies to the tissues. Each antibody binds to specific features (proteins) on the cell surface. The most important antibody that is applied when GIST is suspected is the KIT antibody. […] With rare exceptions, GIST tumors will stain positive for KIT. This means that the cell is manufacturing or using the KIT protein. […] Testing for SDHB for all newly diagnosed patients with stomach tumors and should also be done for patients with partial mutational testing that had no mutation in KIT and PDGFRA (KIT/PDGFRA WT), but had no further mutational testing. […] In approximately 4% of cases KIT is negative by IHC. These KIT-negative cases likely have cells that do not look the same as most GIST cells and may contain PDGFRA (platelet-derived growth factor receptor alpha) mutations.

• #3 Gastrointestinal stromal tumour (GIST): British Sarcoma Group clinical practice guidelines | British Journal of Cancer

  https://www.nature.com/articles/s41416-024-02672-0

  Molecular analysis has predictive value for sensitivity to molecular-targeted therapy, and prognostic value. The inclusion of KIT/PDGFRA molecular analysis in the diagnostic work-up of all GISTs is highly recommended but as a minimum, such analysis should be performed on all the following specimens: resected moderate or high-risk GISTs at any site; resected GISTs showing tumour rupture; biopsies diagnostic of GIST prior to neoadjuvant or adjuvant therapy; specimens from patients with unresectable and/or metastatic GIST; GISTs which are suspected to be syndromic. […] The diagnosis of GIST should be established by a pathologist experienced in the disease and should include the use of IHC and, if necessary, molecular analysis (which should be performed by an accredited laboratory). If initial treatment with imatinib is planned, it is essential to confirm the diagnosis of GIST, since there is a wide differential. It may be necessary to perform a percutaneous core needle biopsy if the tumour is inaccessible to EUS biopsy.

• #3 GIST Diagnosis – The Life Raft Group

  https://liferaftgroup.org/gist-diagnosis/

  Molecular genetic testing is analysis of the DNA from the tumor sample. In GIST, it is also a clinically useful technique that may affect the oncologists choice of therapies. Molecular genetic analysis of GIST is important because of the availability of drug therapies that specifically target the KIT/PDGFRA receptor kinases. These drugs belong to the class of tyrosine kinase inhibitors (TKI), such as imatinib, sunitinib, and regorafenib. […] Approximately 85% of GISTs contain oncogenic mutations in either (mutually exclusive) the KIT or PDGFRA tyrosine kinase receptor. About 12% to 15% of all GISTs have no detectable KIT or PDGFRA mutations. These are known as KIT/PDGFRA WT tumors.

• #3 Gastrointestinal Stromal Tumors (GISTs) | Choose the Right Test

  https://arupconsult.com/content/gastrointestinal-stromal-tumors

  KIT/PDGFRA mutational assessment is important for decision-making and treatment purposes, given that gastrointestinal (GI) stromal tumors (GISTs) have a variety of subtypes with different predictive and prognostic relevance. […] Current therapeutic strategies for GISTs revolve around targeted therapy against PDGFRA, KIT, and related receptor tyrosine kinases. […] Mutational profiling, for example, can identify mutations that are associated with imatinib resistance, such as PDGFRA D842V, wild-type GIST, and KIT exon 9 mutations that confer partial imatinib resistance; tumors with these mutations may respond to higher doses of imatinib. […] Individuals with a GI tract mass suspected to be GIST should undergo biopsy and histologic examination. The results of immunohistochemical staining and mutational analysis may aid the clinician in determining the most appropriate course of action based on the most recent therapeutic guidelines put forth by the National Institutes of Health/National Cancer Institute and other major health organizations.

• #3 Gastrointestinal stromal tumours (GISTs) | Canadian Cancer Society

  https://cancer.ca/en/cancer-information/cancer-types/soft-tissue-sarcoma/what-is-soft-tissue-sarcoma/types-of-soft-tissue-sarcoma/gists

  A recurrent GIST is cancer that has come back (recurred) after it has been treated. If it comes back in the same place or close to where the cancer first started, its called local recurrence. It can also recur in another part of the body. This is called metastatic GIST. […] Understanding how a type of cancer usually grows and spreads helps your healthcare team plan your treatment and future care. If a GIST spreads, it can spread within the abdomen to the liver or peritoneal cavity. It can also spread to the lungs or bones, but this is not common. […] Knowing how quickly the cancer is growing and how likely it is to spread helps doctors plan your treatment. It can also help the healthcare team predict future outcomes (your prognosis) and how the cancer might respond to treatment. […] A pathologist examines a tissue sample from the tumour under a microscope to see how often the cells are dividing. They also check the size of the tumour and where the tumour is in the body. Then GISTs are classified as low or high risk based on their chance of progressing. Low-risk GISTs, which grow slowly, are small and are in the stomach, tend to have a better prognosis.

• #3 Gastrointestinal stromal tumors: a comprehensive review – Parab – Journal of Gastrointestinal Oncology

  https://jgo.amegroups.org/article/view/23883/19709

  Many classification systems have evolved over the years but none have proved to be superior to the other. In 2002, Fletcher and colleagues collaborated to create the NIH classification, the first GIST classification system. […] The gold standard of treatment for GISTs is surgical resection through laparoscopy, however if the patient is unstable then an open laparotomy is the preferred method of treatment. […] The 3 agents approved for the treatment of GISTs are imatinib (Gleevec), sunitinib (Sutent), and ponatinib. […] In addition to surgery and targeted therapy, it is important that patients who fall into the high-risk categories for metastasis follow-up with serial CT scans every three months for five years. […] GISTs are best identified by CT scan but also can be seen on abdominal ultrasound, MRI, and PET. The pathology of GISTs consist of either spindle cells, epithelioid cells, or mixed cell types. GISTs most commonly stain positive for CD117 and DOG-1.

• #3 The standard diagnosis, treatment, and follow-up of gastrointestinal stromal tumors based on guidelines

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4688306/

  Although gastrointestinal stromal tumors (GISTs) are a rare type of cancer, they are the commonest sarcoma in the gastrointestinal tract. […] Many GIST guidelines have been published to guide the diagnosis and treatment of the disease. […] This review describes the current standard diagnosis, treatment, and follow-up of GISTs based on the recommendations of several guidelines and expert consensus. […] It is suggested that diagnosis and treatment based on the guidelines will improve the prognosis of patients and the quality of medical care, as well as control medical costs. […] The pathological diagnosis of GIST depends on the morphology and immunohistochemical findings. […] KIT positivity is a major defining feature for the diagnosis of GIST for a tumor that has morphological features compatible with GIST, although KIT positivity alone is not sufficient for the diagnosis.

• #3 Gastrointestinal stromal tumours (GISTs) | Canadian Cancer Society

  https://cancer.ca/en/cancer-information/cancer-types/soft-tissue-sarcoma/what-is-soft-tissue-sarcoma/types-of-soft-tissue-sarcoma/gists

  Targeted therapy uses drugs to target specific molecules (such as proteins) on or inside cancer cells to stop the growth and spread of cancer and limit harm to normal cells. The targeted therapy drugs used for GISTs are called tyrosine kinase inhibitors. These drugs block many different proteins, including the KIT protein, to help stop or slow cancer cells from growing and spreading. They also prevent tumours from developing new blood vessels.

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