Guzy ślinianki przyusznej – Etiologia i przyczyny

Guzy ślinianki przyusznej
Etiologia i przyczyny

Guzy ślinianki przyusznej stanowią około 80% wszystkich guzów ślinianek, z dominującym udziałem łagodnych zmian (75-80%), w tym gruczolaka wielopostaciowego (60%) i guza Warthina (10%). Złośliwe guzy przyusznicy stanowią 15-30%, z najczęstszymi typami takimi jak rak śluzowo-naskórkowy i rak gruczołowo-torbielowaty. Patogeneza opiera się na mutacjach DNA prowadzących do niekontrolowanego wzrostu komórek, z translokacją chromosomową 4 i 9 aktywującą gen NR4A3 w gruczolakoraku zrazikowym. Teoria wielokomórkowa sugeruje różne komórki macierzyste jako źródło poszczególnych typów guzów. Ryzyko rozwoju guzów zwiększa ekspozycja na promieniowanie jonizujące (zwłaszcza po 15-20 latach od napromieniania), palenie tytoniu (szczególnie w przypadku guza Warthina, z ośmiokrotnie wyższą częstością u palaczy), a także czynniki zawodowe i infekcje wirusowe (EBV, HPV, HIV). Wiek (50-70 lat) i płeć (większa częstość łagodnych guzów u kobiet) również wpływają na epidemiologię.

Etiologia guzów ślinianki przyusznej

Guzy ślinianki przyusznej to zmiany komórek rozpoczynające się w śliniankach przyusznych, stanowiące najczęstszy typ guzów ślinianek (około 80% wszystkich guzów ślinianek). Dokładna przyczyna powstawania tych guzów pozostaje w dużej mierze nieznana, mimo prowadzonych badań¹². Guzy te rozpoczynają się jako rozrost komórek w śliniankach przyusznych, gdy komórki rozwijają zmiany w swoim DNA, co prowadzi do niekontrolowanego wzrostu¹.

Mutacje DNA jako przyczyna guzów ślinianki przyusznej

Guzy ślinianki przyusznej powstają, gdy komórki w tych gruczołach rozwijają zmiany w swoim DNA. DNA zawiera instrukcje mówiące komórce, co ma robić. W zdrowych komórkach DNA daje instrukcje do wzrostu i namnażania się w określonym tempie oraz do obumierania w określonym czasie. W komórkach guza zmiany w DNA przekazują inne instrukcje – nakazują komórkom guza wytwarzać znacznie więcej komórek w szybkim tempie. Komórki guza mogą nadal żyć, gdy zdrowe komórki obumierałyby. Powoduje to nadmiar komórek¹².

Czasami zmiany w DNA przekształcają komórki w komórki nowotworowe. Komórki nowotworowe mogą naciekać i niszczyć zdrowe tkanki. Z czasem komórki nowotworowe mogą oderwać się i rozprzestrzenić do innych części ciała. Gdy nowotwór się rozprzestrzenia, nazywany jest nowotworem przerzutowym³.

Badania wykazały, że u chorych z gruczolakorakiem zrazikowym (trzeci najczęstszy złośliwy nowotwór gruczołów ślinowych) dochodzi do translokacji materiału genetycznego między chromosomami 4 i 9, co było obecne we wszystkich badanych przypadkach. Zwykle takie translokacje w guzach prowadzą do nowej kombinacji genów, które następnie nabywają nowe właściwości onkogenne. W tym przypadku elementy regulacyjne pochodzą z obszaru, gdzie znajdują się geny odpowiedzialne za funkcje śliny, które są wysoce aktywne w gruczołach ślinowych. Po przegrupowaniu chromosomów, te wysoce aktywne elementy regulacyjne znajdują się w pobliżu genu NR4A3, który zwykle jest wyłączony po zakończeniu rozwoju zarodkowego. Sygnały aktywacyjne elementów regulacyjnych w gruczolakoraku zrazikowym powodują ponowne włączenie tego genu. NR4A3 działa jako czynnik transkrypcyjny regulujący aktywność wielu innych genów, które następnie wywołują podział i wzrost komórek, prowadząc ostatecznie do rozpoczęcia wzrostu guza¹².

Istnieją dwie główne teorie dotyczące powstawania guzów gruczołów ślinowych, ale większość badaczy zgadza się z teorią wielokomórkową, według której każdy typ guza powstaje z określonej zróżnicowanej komórki pochodzenia w obrębie jednostki gruczołu ślinowego. Komórki macierzyste wydzielnicze dają początek rakowi śluzowo-naskórkowemu i płaskonabłonkowemu, podczas gdy komórki macierzyste wstawkowe mogą prowadzić do gruczolaków wielopostaciowych, raków gruczołowo-torbielowatych, onkocytomów, gruczolakoraków i gruczolakoraków zrazikowych¹.

Czynniki ryzyka rozwoju guzów ślinianki przyusznej

Choć dokładna przyczyna większości guzów ślinianki przyusznej pozostaje nieznana, zidentyfikowano kilka czynników ryzyka, które mogą zwiększać prawdopodobieństwo ich rozwoju:

Ekspozycja na promieniowanie

Ekspozycja na promieniowanie jest jednym z najbardziej ustalonych czynników ryzyka rozwoju guzów ślinianki przyusznej. Narażenie na promieniowanie jonizujące zwiększa ryzyko wystąpienia nowotworów gruczołów ślinowych, co potwierdziły badania przeprowadzone wśród osób, które przeżyły wybuch bomby atomowej¹. Ekspozycja na promieniowanie medyczne lub ultrafioletowe leczenie terapeutyczne głowy lub szyi oraz ekspozycja na pełne zdjęcia rentgenowskie jamy ustnej również zostały powiązane ze zwiększonym ryzykiem².

Pacjenci, którzy przeszli radioterapię z powodu nowotworów głowy i szyi, mają zwiększone ryzyko rozwoju guzów ślinianki przyusznej, zwłaszcza jeśli gruczoły ślinowe nie były chronione podczas napromieniania¹. Ryzyko to wzrasta po około 15-20 latach od ekspozycji¹².

Związek z tytoniem i alkoholem

Związek między paleniem tytoniu a guzami ślinianki przyusznej jest złożony. Palenie papierosów zostało powiązane z wyższym ryzykiem wystąpienia guza Warthina, łagodnego guza ślinianki przyusznej¹². Badania wykazały, że guzy Warthina są osiem razy częstsze u palaczy w porównaniu z osobami niepalącymi¹. Ważne jest jednak, aby zauważyć, że zarówno alkohol, jak i palenie nie są powiązane z innymi rodzajami guzów gruczołów ślinowych, z wyjątkiem wspomnianych guzów Warthina¹.

Związek między spożyciem alkoholu i tytoniu a złośliwymi guzami przyuszniczymi jest mniej jasny i pozostaje kontrowersyjny, ponieważ niektóre badania wykazują związek pozytywny, a inne brak istotnego związku¹.

Ekspozycje zawodowe

Niektóre badania sugerują, że osoby pracujące z określonymi metalami (pył ze stopu niklu) lub minerałami (pył krzemionkowy) oraz osoby pracujące w górnictwie azbestowym, hydraulice, produkcji wyrobów gumowych i niektórych rodzajach obróbki drewna mogą być narażone na zwiększone ryzyko raka ślinianki przyusznej, ale te powiązania nie są pewne¹².

Inne zawody związane z narażeniem na substancje toksyczne (np. azbest, metalurgia, budownictwo) mogą zwiększać ryzyko rozwoju guzów przyusznicy i innych guzów głowy i szyi¹.

Infekcje wirusowe

Niektóre infekcje wirusowe mogą być powiązane z pewnymi guzami ślinianki. Badania wykazały, że niektóre rzadkie typy raka ślinianki mogą występować częściej u osób z określonymi zakażeniami wirusowymi, takimi jak wirus Epsteina-Barr i wirus brodawczaka ludzkiego (HPV)¹².

Rak nasieniakopodobny, bardzo rzadki typ raka ślinianki, jest związany z wirusem Epsteina-Barr¹. Osoby z wirusem ludzkiego niedoboru odporności (HIV) również są narażone na ryzyko raka ślinianki².

Czynniki genetyczne

Czynniki genetyczne odgrywają istotną rolę w rozwoju guzów ślinianki przyusznej w niektórych przypadkach, chociaż jest to mniej powszechne¹. Ryzyko rozwoju raka ślinianki przyusznej może być zwiększone, jeśli ktoś inny w rodzinie miał tę chorobę¹.

Niektóre osoby wydają się dziedziczyć słabą zdolność do detoksykacji (rozkładu) niektórych rodzajów substancji rakotwórczych. Osoby te są bardziej wrażliwe na rakotwórcze działanie dymu tytoniowego i niektórych przemysłowych substancji chemicznych¹.

Wiek i płeć

Ryzyko zachorowania na guzy ślinianki przyusznej wzrasta wraz z wiekiem. Większość guzów przyuszniczych występuje u osób w wieku od 50 do 70 lat¹. Niektóre typy łagodnych guzów przyuszniczych, takie jak gruczolak wielopostaciowy, są częstsze u kobiet².

Z wyjątkiem guzów Warthina, łagodne guzy ślinianki przyusznej częściej występują u kobiet niż u mężczyzn. Mediana wieku występowania tych guzów przypada na piątą dekadę życia. Guzy przyusznicy występują najczęściej u osób rasy kaukaskiej¹.

Potencjalne czynniki etiologiczne budzące kontrowersje

Telefony komórkowe

Niektóre badania sugerują związek między intensywnym używaniem telefonów komórkowych a zwiększonym ryzykiem łagodnych i złośliwych guzów przyusznicy¹². Jednak inne badania nie znalazły dowodów na istnienie takiego związku¹. Obecnie nie ma wystarczających danych medycznych i badań, aby jednoznacznie zidentyfikować nadmierne korzystanie z telefonów komórkowych jako przyczynę guzów przyusznicy¹.

Dieta

Niektóre badania wykazały, że dieta uboga w warzywa i bogata w tłuszcze zwierzęce może zwiększać ryzyko raka ślinianki, ale potrzebne są dalsze badania, aby potwierdzić to potencjalne powiązanie¹.

Masa ciała

Retrospektywne badanie przeprowadzone przez Kadletza i wsp. sugeruje, że wysoki wskaźnik masy ciała (BMI) i zespół metaboliczny mogą zwiększać ryzyko powstawania guza Warthina. Badacze stwierdzili BMI wynoszące 29,1 u pacjentów z guzem Warthina, w porównaniu z 26,2 u osób z innymi rodzajami łagodnych guzów przyusznicy. Ponadto pacjenci z guzem Warthina mieli 62,4% częstość występowania chorób współistniejących związanych z zespołem metabolicznym, w porównaniu z 35,2% u innych¹.

Różnice między guzami łagodnymi i złośliwymi

Około 75-80% guzów ślinianki przyusznej to zmiany łagodne¹. Najczęstszym typem łagodnego guza jest gruczolak wielopostaciowy (około 60% guzów przyusznicy), a następnie guz Warthina (około 10% guzów przyusznicy)¹.

Guzy złośliwe stanowią około 15-30% guzów przyusznicy; najczęściej zgłaszanym z nich jest rak śluzowo-naskórkowy, a następnie rak gruczołowo-torbielowaty¹. Chociaż około 70% wszystkich guzów przyusznicy jest łagodnych, biorąc pod uwagę ogólnie wyższą częstość występowania guzów ślinianki przyusznej w porównaniu z innymi gruczołami ślinowymi, 70% wszystkich złośliwych nowotworów gruczołów ślinowych powstaje w śliniance przyusznej¹.

Rzadko guz może być złośliwą transformacją z wcześniejszego łagodnego guza (jak w przypadku raka powstającego w obrębie wcześniejszego łagodnego gruczolaka wielopostaciowego)¹. Gruczolaków wielopostaciowych mogą ulegać złośliwej transformacji, ale ta transformacja zwykle występuje tylko wtedy, gdy łagodny guz był obecny przez 15 do 20 lat¹.

Najczęstszym typem nieprawidłowej masy w śliniance przyusznej jest wolno rosnący łagodny (niezłośliwy) guz ślinianki przyusznej. Guz stopniowo zwiększa rozmiar gruczołu. Niektóre z tych guzów mogą być złośliwe¹.

Podsumowanie etiologii guzów ślinianki przyusznej

Dokładne przyczyny większości guzów ślinianki przyusznej pozostają nieznane, mimo prowadzonych badań. Główną rolę w powstawaniu tych guzów odgrywają mutacje DNA prowadzące do niekontrolowanego wzrostu komórek. Zidentyfikowano kilka czynników ryzyka, w tym ekspozycję na promieniowanie, palenie tytoniu (głównie związane z guzami Warthina), niektóre infekcje wirusowe oraz narażenie zawodowe na określone substancje chemiczne. Wiek i płeć również wpływają na ryzyko rozwoju tych guzów¹²³.

Potrzebne są dodatkowe badania, aby lepiej zrozumieć etiologię guzów ślinianki przyusznej oraz zidentyfikować skuteczne strategie profilaktyki i leczenia. Prowadzone są badania genetyczne mające na celu określenie, czy dziedziczność może odgrywać rolę w rozwoju guzów przyusznicy¹.

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Materiały źródłowe

#1 Parotid tumors – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/parotid-tumor/symptoms-causes/syc-20578986
Parotid tumors are growths of cells that start in the parotid glands. […] It’s not clear what causes parotid tumors. These tumors start as a growth of cells in the parotid glands. […] Parotid tumors happen when cells in the parotid glands develop changes in their DNA. […] Sometimes the changes in the DNA turn the cells into cancer cells.
#1 Parotid tumors | UM Health-Sparrow
https://www.uofmhealthsparrow.org/departments-conditions/conditions/parotid-tumors
It’s not clear what causes parotid tumors. These tumors start as a growth of cells in the parotid glands. […] Parotid tumors happen when cells in the parotid glands 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 tumor cells, the DNA changes give different instructions. The changes tell the tumor cells to grow and multiply quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells. […] Sometimes the changes in the DNA turn the cells into cancer cells. Cancer cells can invade and destroy healthy body tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it’s called metastatic cancer.
#1 Salivary gland tumors – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/salivary-gland-cancer/symptoms-causes/syc-20354151
Salivary gland tumors can happen in any salivary gland. Most salivary gland tumors occur in the parotid gland. Of these, most aren’t cancer. For every five parotid gland tumors, on average, only one is found to be cancerous. […] The cause of many salivary gland tumors isn’t known. Healthcare professionals have identified some things that raise the risk of salivary gland tumors. These include smoking and radiation therapy for cancer. Not everyone with a salivary gland tumor has these risk factors, though. More research is needed to find out exactly what causes these tumors. […] Salivary gland tumors happen when cells in a salivary gland 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 also tell the cells to die at a set time. In tumor cells, the changes give different instructions. The changes tell the tumor cells to make many more cells quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells. […] Sometimes the changes in the DNA turn the cells into cancer cells. Cancer cells can invade and destroy healthy body tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it’s called metastatic cancer.
#1 Genetic causes of tumors in salivary glands | ScienceDaily
https://www.sciencedaily.com/releases/2019/01/190130103809.htm
Acinic cell carcinoma is the third most common malignant form of salivary gland cancer. These tumors are similar to normal salivary gland tissue and occur most frequently in the parotid gland. Until now, the molecular causes for the illness were unknown. […] Using genome sequencing on tumour tissue, the researchers identified a translocation of genetic material between chromosomes 4 and 9, which was present in all acinic cell carcinomas examined. Typically, such translocations in tumours lead to a new combination of genes, which then acquire new oncogenic, i.e. carcinogenic, properties. In the case of acinic cell carcinomas, the translocation which has now been discovered causes regulatory elements of DNA to be transferred from an active chromosome region to a normally inactive oncogene.
#1 Parotid Cancer – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK538340/
There are two main theories of how salivary gland tumors arise, but the consensus is with the multicellular theory, that each tumor type forms from a specific differentiated cell of origin within the salivary gland unit. Excretory stem cells give rise to mucoepidermoid and squamous cell carcinomas, while intercalated stem cells can lead to pleomorphic adenomas, adenoid cystic carcinomas, oncocytomas, adenocarcinomas, and acinic cell carcinomas. […] Radiation exposure has been linked to parotid gland carcinomas 15 years after the event. Cigarette smoking and alcohol is associated with head and neck squamous cell carcinoma, skin malignancies in the head and neck have been known to metastases to the parotid glands. Some cases of a link between occupational exposure to silica dust and nitrosamines have been reported.[3] […] It is important to note that both alcohol and smoking are not linked to salivary gland tumors, except for Warthin tumors.
#1 An overview of the rare parotid gland cancer | Head & Neck Oncology | Full Text
https://headandneckoncology.biomedcentral.com/articles/10.1186/1758-3284-3-40
Partly owning to the rarity of parotid gland cancer, its etiology has not been thoroughly studied and the factors responsible for its carcinogenesis are unclear. […] However, one of the well-established risk factors is exposure to ionizing radiation, as supported by studies on atomic bomb survivors. […] Medical radiation or ultraviolet light therapeutic treatments to the head or neck and exposures to full-mouth dental X-rays have also been linked to an increased risk. […] Additionally, nitroso compounds have induced parotid gland tumors in laboratory mice. The presence of nitroso compounds in rubbers could explain the higher incidence of parotid gland cancer in rubber industrial workers.
#1 What Are the Risk Factors for Salivary Gland Cancer? | American Cancer Society
https://www.cancer.org/cancer/types/salivary-gland-cancer/causes-risks-prevention/risk-factors.html
A few risk factors are known to make a person more likely to develop salivary gland cancer, but most salivary gland cancers start without any clear cause. […] Radiation treatment to the head and neck area for other medical reasons increases your risk of salivary gland cancer, especially if your salivary glands were not protected during the radiation. […] Smoking cigarettes has been linked to a higher risk of Warthin tumor, a benign salivary gland tumor, but not other types of salivary gland cancers. […] Some studies have suggested that people who work with certain metals (nickel alloy dust) or minerals (silica dust), and people who work in asbestos mining, plumbing, rubber products manufacturing, and some types of woodworking may be at increased risk for salivary gland cancer, but these links are not certain.
#1 Salivary Gland Tumours: Causes, Symptoms, and Treatment
https://patient.info/doctor/salivary-gland-tumours
About 80% of salivary gland cancers occur in the parotid gland. […] Certain ethnic groups (eg, Inuit populations) have a higher rate of salivary gland cancers which is maintained even after migration to a low incidence area. The responsible environmental or genetic factors are unknown. […] Radiation to the neck increases the risk of malignancy of salivary glands with a 15- to 20-year latency. […] Smoking is an important risk factor for the development of Warthin’s tumours but its relationship to malignant parotid tumours is less clear. Warthin’s tumours are eight times more common in smokers compared with non-smokers. […] Some studies have suggested an association between high use of mobile phones and an increased risk of benign and malignant parotid tumours. However, others have found no evidence of such a relationship.
#1 Malignant Salivary Gland Tumors – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK563022/
Compared to other head and neck cancers, the risk of developing malignant salivary gland tumors from exposure to tobacco and alcohol has been controversial, with several studies noting both positive association and no appreciable association. […] Chronic inflammation of the salivary glands has not been established as a risk factor. However, autoimmune conditions such as Sjogren syndrome may predispose an individual to develop a salivary gland malignancy such as lymphoma. […] The most significant risk factor for primary SCC of the salivary glands appears to be prior gland radiation. […] The development of lymphoma from Sjogren syndrome is theorized to be due to prolonged B-cell activity and survival. Sjogren syndrome is associated with excessive expression of cytokines, chemokines, and inflammatory factors such as interferon (IFN) and B-cell activating factor.
#1 Causas of Parotid Tumours | PortalCLÃNIC
https://www.clinicbarcelona.org/en/assistance/diseases/parotid-tumours/causes
A family history of parotid tumours or other types of cancer slightly increases the risk of developing it. […] Some occupations, such as those involving exposure to toxic chemicals (e.g. asbestos, metallurgy, construction) can increase the risk of developing parotid and other head and neck tumours. […] Genetic factors play a significant role in the development of parotid tumours in some cases, although this is less common.
#1 What Are the Risk Factors for Salivary Gland Cancer? | American Cancer Society
https://www.cancer.org/cancer/types/salivary-gland-cancer/causes-risks-prevention/risk-factors.html
Some viral infections might be associated with certain salivary gland tumors. […] Certain high-risk types of human papillomavirus (HPV) has been found in some mucoepidermoid cancers, but more studies are needed to say for sure if there is a link. […] People with human immunodeficiency virus (HIV) are also at risk for salivary gland cancers. […] Lymphoepithelial cancer, a very rare type of salivary gland cancer, is associated with the Epstein-Barr virus. […] Some studies have found that a diet low in vegetables and high in animal fat might increase the risk of salivary gland cancer, but more research is needed to confirm this possible link. […] One study has suggested an increased risk of parotid gland tumors among heavy cell phone users.
#1 Risks and causes | Salivary gland cancer | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/salivary-gland-cancer/risks-causes
We dont know what causes salivary gland cancer but several factors can increase your risk. […] You are at higher risk of developing salivary gland cancer if you have been exposed to radiation. […] Your risk of developing salivary gland cancer may be increased if someone else in your family has had it. […] There are often stories about potential causes of cancer in the media. It isnt always clear which ideas are supported by evidence.
#1 What Causes Salivary Gland Cancer? | American Cancer Society
https://www.cancer.org/cancer/types/salivary-gland-cancer/causes-risks-prevention/what-causes.html
Inherited mutations of oncogenes or tumor suppressor genes rarely cause these cancers, but some people seem to inherit a poor ability to detoxify (break down) certain types of cancer-causing chemicals. These people are more sensitive to the cancer-causing effects of tobacco smoke, and certain industrial chemicals.
#1 Causas of Parotid Tumours | PortalCLÃNIC
https://www.clinicbarcelona.org/en/assistance/diseases/parotid-tumours/causes
The specific causes of parotid tumours are not known, but several risk factors have been identified with the disease developing. […] Most parotid tumours occur in people between 50 and 70 years old. Also, some types of benign parotid tumours, such as pleomorphic adenoma, are more common in women. […] Being exposed to radiation in the head and neck, either as part of an earlier medical treatment or from work-related causes, has been associated with an increased risk of developing parotid tumours. […] Smoking and alcohol use have been linked to an increased risk of developing certain types of head and neck tumours, including parotid tumours. The type of glandular tumour most related to tobacco use is Warthin’s tumour. […] Although not a direct cause, some research suggests that certain viral infections, such as Epstein-Barr virus (EBV), may increase the risk of developing malignant parotid tumours.
#1 Benign Parotid Tumors: Practice Essentials, Anatomy, Incidence and Etiology
https://emedicine.medscape.com/article/1289560-overview
Approximately 2500 new cases of salivary gland neoplasms are diagnosed each year. Parotid neoplasms account for 80% of salivary neoplasms. Of parotid masses, 75% are neoplastic; the remaining 25% are nonneoplastic infiltrative processes, such as cysts and inflammation. Of parotid neoplasms, 70-80% are benign. Except for Warthin tumors, benign tumors of the parotid gland are more likely to occur in women than in men. The median age for occurrence of these tumors is in the fifth decade of life. Parotid tumors occur most commonly in Caucasians. The etiology of these tumors is unknown, but the possibility of an adenoma gene currently is under investigation for its involvement in the development of pleomorphic adenomas. […] A retrospective study by Kadletz et al suggested that a high body mass index (BMI) and metabolic syndrome may increase the risk of Warthin tumor formation. The investigators found a BMI of 29.1 in patients with Warthin tumor, compared with 26.2 in persons with other types of benign parotid tumors. Moreover, patients with Warthin tumor had a 62.4% rate of metabolic syndrome associated comorbidities, compared with 35.2% in the others.
#1 Parotid Tumor Cause, Parotid Tumor Genetic, Salivary Tumor Cause
https://parotidpatientproject.org/parotid-education/causes-of-parotid-tumors.html
The causes of parotid tumors are generally unknown at this time. […] While tobacco smoking has the highest association with parotid tumors, that association is only with certain parotid tumors, such as a Warthin tumor. […] There is currently no knowledge of genetic disorders being associated with primary parotid tumors. Other factors that have been associated with causing malignant parotid tumors are ionizing radiation and suppression of the immune system. […] There has been some indication that people who have received radiation near the head and neck area during treatment of other conditions could potentially be at risk of developing a parotid tumor. […] Although there have been some recent research studies that have suggested that excessive use of cell phones could contribute to the development of parotid tumors, there is not enough medical data and research currently available to definitively identify excessive cell phone usage as a cause for parotid tumors.
#1 Parotid neoplasms: analysis of 600 patients attended at a single institution | Brazilian Journal of Otorhinolaryngology
https://www.elsevier.es/en-revista-brazilian-journal-otorhinolaryngology-english-edition–497-articulo-parotid-neoplasms-analysis-600-patients-S1808869415304869
Salivary gland tumors are rare, generally benign and affect mainly the parotid gland. […] The parotid gland is the most frequent site about 70% of cases. […] About 80% of parotid tumors are benign, the most common being the pleomorphic adenoma (60% of parotid tumors), followed by Warthin’s tumor (10% of parotid tumors). […] The most common salivary gland malignancy is the mucoepidermoid carcinoma, which involves mostly the parotid gland, followed by the minor, submandibulary and sublingual salivary glands. […] The main symptom in patients with parotid neoplasms is a lump in the parotid area. […] The treatment of choice for benign and malignant parotid tumors is partial or total parotidectomy, according to the extent of the tumor. […] Local, regional and distance recurrence rates are 40%, 15% and 11% each, and worsened the prognosis.
#1 Parotid neoplasms: analysis of 600 patients attended at a single institution | Brazilian Journal of Otorhinolaryngology
https://www.elsevier.es/en-revista-brazilian-journal-otorhinolaryngology-english-edition–497-articulo-parotid-neoplasms-analysis-600-patients-S1808869415304869
The pleomorphic adenoma and Warthin’s tumor are the most common benign tumors. […] Malignant tumors comprise about 15 to 30% of parotid tumors; the most commonly reported of these is the mucoepidermoid carcinoma, followed by the cystic adenoid carcinoma. […] The treatment of choice for benign tumors of the parotid gland is parotidectomy, preserving the facial nerve. […] Total parotidectomy in benign tumors is done when the deep lobe of the parotid is involved. […] Rupture of the capsule during surgical resection and positive microscopic margins may lead to recurrences. […] Adjuvant radiotherapy has been shown to be effective for improving local control and increased survival. […] Recurrence rates were 10% (local), 8% (regional), and 9% (distance), lower than most of published results in the international literature.
#1 Parotid gland tumors | Radiology Reference Article | Radiopaedia.org
https://radiopaedia.org/articles/parotid-gland-tumors-1?lang=us
Parotid gland tumors include a variety of benign and malignant entities that are also found in other salivary glands (see salivary gland tumors). […] The demographic of affected individuals will vary according to the tumor type. Generally, parotid gland tumors are encountered in middle age group. […] One entity notable from a demographic point of view: lymphomatous papillary cystadenomas (Warthin tumors) are almost only ever seen in the parotid gland and are strongly associated with elderly male individuals. […] Although approximately 70% of all parotid tumors are benign, given the overall higher frequency of tumors of the parotid gland compared to other salivary glands, 70% of all malignant salivary gland cancers arise in the parotid.
#1 Malignant Neoplasms (Salivary Gland Tumors) | Stanford Health Care
https://stanfordhealthcare.org/medical-conditions/cancer/salivary-gland-cancer/salivary-gland-cancer-types/malignant-salivary-gland-tumors-neoplasms.html
About 20% of parotid tumors are malignant, with higher percentages for children, for the submandibular gland, and for intraoral minor salivary glands. […] Rarely a tumors may be malignant transformation from a prior benign tumor (as in a carcinoma arising within a prior benign pleomorphic adenoma).
#1 Salivary Gland Tumors – Ear, Nose, and Throat Disorders – MSD Manual Professional Edition
https://www.msdmanuals.com/professional/ear-nose-and-throat-disorders/tumors-of-the-head-and-neck/salivary-gland-tumors
Most salivary gland tumors are benign and occur in the parotid glands. […] About 85% of salivary gland tumors occur in the parotid glands, followed by the submandibular and minor salivary glands, and about 1% occur in the sublingual glands. […] In general, the risk of malignancy is greater in smaller salivary glands than in larger salivary glands (eg, the parotid gland has a lower risk of malignancy than minor salivary glands). […] Pleomorphic adenomas (mixed-type tumors) can undergo malignant transformation, but this transformation usually occurs only after the benign tumor has been present for 15 to 20 years. […] Mucoepidermoid carcinoma is the most common salivary gland cancer, typically occurring in people in their 20s to 50s. […] Acinic cell carcinoma, a common parotid tumor, occurs in people in their 40s and 50s. […] Only about 20 to 25% of salivary gland tumors are malignant; the parotid gland is most commonly affected.
#1 Salivary gland tumors: MedlinePlus Medical EncyclopediaLock
https://medlineplus.gov/ency/article/001040.htm
Salivary gland tumors are abnormal cells growing in the gland or in the tubes (ducts) that drain the salivary glands. […] Salivary gland tumors are rare. Swelling of the salivary glands is mostly due to: cirrhosis of the liver, other cancers, salivary duct stones, salivary gland infections, dehydration, sarcoidosis, SjÃ¶gren syndrome. […] The most common type of salivary gland tumor is a slow-growing noncancerous (benign) tumor of the parotid gland. The tumor gradually increases the size of the gland. Some of these tumors can be cancerous (malignant).
#1 Ear Nose and Throat – Everything You Need To Know About Parotid Tumors
https://www.entlubbock.com/blog/parotid-tumors/
Only about six in 100,000 people will experience a parotid gland tumor. Far fewer will have a cancerous parotid tumor. […] Unlike a lot of other tumors, most parotid tumors dont have clear causes, like smoking or alcohol consumption, to indicate who might be at higher risk. […] Some skin cancers have been known to spread to the parotid glands. And one type of parotid tumor, a Warthins benign tumor, has been connected to smoking. […] But for the time being, it seems that some people are just more prone to parotid tumors than others. Genetic research is underway to try to determine if heredity might play a role in the development of parotid tumors.
#2 Parotid Gland Tumors: Symptoms, Causes & Treatment
https://my.clevelandclinic.org/health/diseases/parotid-tumor
Abnormal masses or tumors that develop on your parotid gland may be benign (non-cancerous) or malignant (cancerous). […] Experts arent sure exactly what causes these cancerous and noncancerous tumors. Research suggests some common possible causes include using tobacco or having radiation therapy for head and neck cancer.
#2 Parotid tumors | UM Health-Sparrow
https://www.uofmhealthsparrow.org/departments-conditions/conditions/parotid-tumors
It’s not clear what causes parotid tumors. These tumors start as a growth of cells in the parotid glands. […] Parotid tumors happen when cells in the parotid glands 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 tumor cells, the DNA changes give different instructions. The changes tell the tumor cells to grow and multiply quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells. […] Sometimes the changes in the DNA turn the cells into cancer cells. Cancer cells can invade and destroy healthy body tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it’s called metastatic cancer.
#2 Genetic causes of tumors in salivary glands | ScienceDaily
https://www.sciencedaily.com/releases/2019/01/190130103809.htm
In this unusual form of translocation, the regulatory elements come originally from an area where genes which are responsible for functions in saliva and are highly active in salivary glands are located. When the chromosomes are rearranged, these highly active regulatory elements come into the vicinity of gene NR4A3, which is usually switched off once embryonic development has been completed. The activation signals of the regulatory elements in the acinic cell carcinoma cause the gene to be switched on again. NR4A3 acts as a transcriptional factor to regulate the activity of a number of other genes, which then trigger cell division and growth, leading ultimately to the tumour starting to grow. […] Similar genetic rearrangements of regulatory elements of DNA as a potential cause of malignant tumours have also recently been observed in brain tumours in children, referred to in this context as 'enhancer hijacking’.
#2 An overview of the rare parotid gland cancer | Head & Neck Oncology | Full Text
https://headandneckoncology.biomedcentral.com/articles/10.1186/1758-3284-3-40
Partly owning to the rarity of parotid gland cancer, its etiology has not been thoroughly studied and the factors responsible for its carcinogenesis are unclear. […] However, one of the well-established risk factors is exposure to ionizing radiation, as supported by studies on atomic bomb survivors. […] Medical radiation or ultraviolet light therapeutic treatments to the head or neck and exposures to full-mouth dental X-rays have also been linked to an increased risk. […] Additionally, nitroso compounds have induced parotid gland tumors in laboratory mice. The presence of nitroso compounds in rubbers could explain the higher incidence of parotid gland cancer in rubber industrial workers.
#2 Salivary Gland Tumours: Causes, Symptoms, and Treatment
https://patient.info/doctor/salivary-gland-tumours
About 80% of salivary gland cancers occur in the parotid gland. […] Certain ethnic groups (eg, Inuit populations) have a higher rate of salivary gland cancers which is maintained even after migration to a low incidence area. The responsible environmental or genetic factors are unknown. […] Radiation to the neck increases the risk of malignancy of salivary glands with a 15- to 20-year latency. […] Smoking is an important risk factor for the development of Warthin’s tumours but its relationship to malignant parotid tumours is less clear. Warthin’s tumours are eight times more common in smokers compared with non-smokers. […] Some studies have suggested an association between high use of mobile phones and an increased risk of benign and malignant parotid tumours. However, others have found no evidence of such a relationship.
#2 Parotid Tumor Cause, Parotid Tumor Genetic, Salivary Tumor Cause
https://parotidpatientproject.org/parotid-education/causes-of-parotid-tumors.html
The causes of parotid tumors are generally unknown at this time. […] While tobacco smoking has the highest association with parotid tumors, that association is only with certain parotid tumors, such as a Warthin tumor. […] There is currently no knowledge of genetic disorders being associated with primary parotid tumors. Other factors that have been associated with causing malignant parotid tumors are ionizing radiation and suppression of the immune system. […] There has been some indication that people who have received radiation near the head and neck area during treatment of other conditions could potentially be at risk of developing a parotid tumor. […] Although there have been some recent research studies that have suggested that excessive use of cell phones could contribute to the development of parotid tumors, there is not enough medical data and research currently available to definitively identify excessive cell phone usage as a cause for parotid tumors.
#2 Salivary gland cancer: Is it preventable?
https://www.medicalnewstoday.com/articles/how-to-prevent-salivary-gland-cancer
People who work with the following chemicals and substances may also be at a higher risk of developing certain cancers, such as salivary gland cancer: nickel alloy dust, silica dust, asbestos mining, rubber product manufacture, sawdust in some types of woodworking, pesticides, chemicals used in leather production, industrial solvents, hair dye or hairspray. […] Experts do not know the exact cause of salivary gland cancer. However, certain factors may increase an individuals risk of developing it. These risk factors include older age, exposure to radiation, smoking, certain viral infections, such as HPV, EBV, and HIV. […] Salivary gland cancer comprises a rare group of cancers with unclear causes. Due to the rarity of this type of cancer, there is limited research into it. This makes it difficult to determine exactly how to prevent it. […] However, avoiding tobacco use and exposure to radiation and workplace substances, such as asbestos, may reduce a persons risk of developing this type of cancer.
#2 Salivary Gland Cancer: Symptoms, Causes & Treatment
https://my.clevelandclinic.org/health/diseases/17965-salivary-gland-cancer
Most salivary gland tumors both malignant and benign start in your parotid glands. […] Studies have shown that some rare types of salivary gland cancer may occur more commonly in people with certain viral infections, like Epstein-Barr virus and human papillomavirus (HPV). Still, these infections dont cause salivary gland cancer. More research is needed to understand the connection. […] The exact cause of most salivary gland cancers is unknown. […] Salivary gland cancer also occurs within the microscopic minor salivary glands. […] Left untreated, pieces of these tumors can break away and spread to other parts of your body through your bloodstream or lymphatic system (metastasize). […] Cancer thats metastasized is more challenging to treat than cancer that stays in your salivary gland.
#2 What Are the Risk Factors for Salivary Gland Cancer? | American Cancer Society
https://www.cancer.org/cancer/types/salivary-gland-cancer/causes-risks-prevention/risk-factors.html
Some viral infections might be associated with certain salivary gland tumors. […] Certain high-risk types of human papillomavirus (HPV) has been found in some mucoepidermoid cancers, but more studies are needed to say for sure if there is a link. […] People with human immunodeficiency virus (HIV) are also at risk for salivary gland cancers. […] Lymphoepithelial cancer, a very rare type of salivary gland cancer, is associated with the Epstein-Barr virus. […] Some studies have found that a diet low in vegetables and high in animal fat might increase the risk of salivary gland cancer, but more research is needed to confirm this possible link. […] One study has suggested an increased risk of parotid gland tumors among heavy cell phone users.
#2 Causas of Parotid Tumours | PortalCLÃNIC
https://www.clinicbarcelona.org/en/assistance/diseases/parotid-tumours/causes
The specific causes of parotid tumours are not known, but several risk factors have been identified with the disease developing. […] Most parotid tumours occur in people between 50 and 70 years old. Also, some types of benign parotid tumours, such as pleomorphic adenoma, are more common in women. […] Being exposed to radiation in the head and neck, either as part of an earlier medical treatment or from work-related causes, has been associated with an increased risk of developing parotid tumours. […] Smoking and alcohol use have been linked to an increased risk of developing certain types of head and neck tumours, including parotid tumours. The type of glandular tumour most related to tobacco use is Warthin’s tumour. […] Although not a direct cause, some research suggests that certain viral infections, such as Epstein-Barr virus (EBV), may increase the risk of developing malignant parotid tumours.
#2 Salivary gland tumors – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/salivary-gland-cancer/symptoms-causes/syc-20354151
Salivary gland tumors can happen in any salivary gland. Most salivary gland tumors occur in the parotid gland. Of these, most aren’t cancer. For every five parotid gland tumors, on average, only one is found to be cancerous. […] The cause of many salivary gland tumors isn’t known. Healthcare professionals have identified some things that raise the risk of salivary gland tumors. These include smoking and radiation therapy for cancer. Not everyone with a salivary gland tumor has these risk factors, though. More research is needed to find out exactly what causes these tumors. […] Salivary gland tumors happen when cells in a salivary gland 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 also tell the cells to die at a set time. In tumor cells, the changes give different instructions. The changes tell the tumor cells to make many more cells quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells. […] Sometimes the changes in the DNA turn the cells into cancer cells. Cancer cells can invade and destroy healthy body tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it’s called metastatic cancer.
#3 Salivary gland tumors – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/salivary-gland-cancer/symptoms-causes/syc-20354151
Salivary gland tumors can happen in any salivary gland. Most salivary gland tumors occur in the parotid gland. Of these, most aren’t cancer. For every five parotid gland tumors, on average, only one is found to be cancerous. […] The cause of many salivary gland tumors isn’t known. Healthcare professionals have identified some things that raise the risk of salivary gland tumors. These include smoking and radiation therapy for cancer. Not everyone with a salivary gland tumor has these risk factors, though. More research is needed to find out exactly what causes these tumors. […] Salivary gland tumors happen when cells in a salivary gland 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 also tell the cells to die at a set time. In tumor cells, the changes give different instructions. The changes tell the tumor cells to make many more cells quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells. […] Sometimes the changes in the DNA turn the cells into cancer cells. Cancer cells can invade and destroy healthy body tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it’s called metastatic cancer.
#3 Parotid Gland Tumor: What You May Need To Know
https://www.healthline.com/health/parotid-gland-tumor
Parotid gland tumors develop in the parotid gland, which is the largest of the salivary glands. […] The cause of many salivary gland tumors is unknown. Its possible that a variety of genetic, environmental, and lifestyle factors are at work. […] You may be more likely to have a parotid gland tumor if youve been exposed to certain types of radiation at work or undergone radiation therapy on your head and neck. Radiation is also associated with malignancy, while theres no link for benign tumors. […] Youre also at a greater chance of a parotid gland tumor if youre older.