Rak jelita cienkiego – Etiologia i przyczyny

Rak jelita cienkiego
Etiologia i przyczyny

Rak jelita cienkiego stanowi około 3% wszystkich nowotworów złośliwych przewodu pokarmowego i charakteryzuje się transformacją nowotworową komórek jelita cienkiego na skutek mutacji genetycznych, w tym aktywacji onkogenów i dezaktywacji genów supresorowych, takich jak MLH1, MSH2, MSH6, PMS2 (zespół Lyncha), APC (FAP) oraz STK11 (zespół Peutza-Jeghersa). Ryzyko rozwoju raka jelita cienkiego jest szczególnie podwyższone u pacjentów z dziedzicznymi zespołami genetycznymi (około 20% przypadków), przewlekłymi chorobami zapalnymi jelit (choroba Leśniowskiego-Crohna zwiększa ryzyko 8-krotnie, celiakia 10-krotnie), a także u osób z mukowiscydozą, obniżoną odpornością czy po leczeniu raka jelita grubego. Typowy wiek zachorowania to powyżej 60 lat, z przewagą mężczyzn (60%) i wyższą częstością u Afroamerykanów.

Etiologia raka jelita cienkiego

Rak jelita cienkiego (Small Bowel Cancer) jest rzadkim typem nowotworu przewodu pokarmowego, stanowiącym zaledwie około 3% wszystkich nowotworów złośliwych układu pokarmowego w Stanach Zjednoczonych¹². Dokładna przyczyna powstawania raka jelita cienkiego nie jest w pełni poznana, podobnie jak w przypadku wielu innych nowotworów złośliwych. Badacze nie do końca rozumieją, co powoduje, że komórki jelita cienkiego ulegają transformacji nowotworowej³⁴. Wiemy jednak, że podstawą tego procesu jest wystąpienie szeregu zmian genetycznych, które prowadzą do niekontrolowanego podziału komórek i tworzenia guza nowotworowego⁵⁶.

Zmiany genetyczne w raku jelita cienkiego

Rak jelita cienkiego rozwija się, gdy w komórkach jelita cienkiego dochodzi do zmian w DNA, które zmieniają normalne instrukcje dla komórki. Te mutacje sprawiają, że komórki mnożą się szybko, kontynuują życie, gdy zdrowe komórki powinny umrzeć w ramach naturalnego cyklu życiowego, oraz mogą naciekać i niszczyć zdrowe tkanki⁷. Naukowcy odkryli pewne zmiany DNA w komórkach raka jelita cienkiego, które wydają się pomagać im rosnąć i rozprzestrzeniać się⁸.

Nowotwory mogą być powodowane przez zmiany DNA, które aktywują onkogeny lub dezaktywują geny supresorowe nowotworów. Jedną z przyczyn tych nowotworów uważa się problemy z genami supresorowymi, które normalnie pomagają naprawiać uszkodzone DNA⁹. Zmiany genetyczne mogą narastać przez całe życie człowieka, co może tłumaczyć, dlaczego rak jelita cienkiego dotyka głównie osoby starsze¹⁰.

Patogeneza i rozwój nowotworu

Wielu ekspertów uważa, że rak jelita cienkiego rozwija się podobnie do raka jelita grubego. Proces ten rozpoczyna się od polipa (nienowotworowego rozrostu) na wewnętrznej ścianie jelita, który z czasem może przekształcić się w nowotwór złośliwy¹¹¹². Adenokarcinoma jelita cienkiego, najczęstszy typ tego nowotworu, prawdopodobnie rozwija się głównie z gruczolaków¹³.

Chroniczne zapalenie w obrębie jelita cienkiego jest powiązane z mutacjami i nadmiernym namnażaniem się komórek. Z czasem zapalenie może powodować zmiany w komórkach jelita cienkiego, prowadząc do mutacji i niekontrolowanego namnażania się¹⁴. Teoria ta może wyjaśniać zwiększone ryzyko raka jelita cienkiego u osób z chorobami zapalnymi jelit, takimi jak choroba Leśniowskiego-Crohna.

Czynniki ryzyka i predyspozycje genetyczne

Pomimo że dokładna przyczyna raka jelita cienkiego pozostaje nieznana, badacze zidentyfikowali szereg czynników ryzyka, które mogą zwiększać prawdopodobieństwo jego rozwoju¹⁵. Czynniki te obejmują predyspozycje genetyczne, choroby współistniejące oraz czynniki środowiskowe i związane ze stylem życia.

Zespoły dziedziczne

Osoby z pewnymi dziedzicznymi zespołami genetycznymi mają znacznie podwyższone ryzyko rozwoju raka jelita cienkiego. Do najważniejszych z nich należą:

Zespół Lyncha (wcześniej znany jako dziedziczny rak jelita grubego niezwiązany z polipowatością, HNPCC) – jest spowodowany mutacjami germinalnymi w genach naprawy błędnie sparowanych zasad DNA (MMR): MLH1, MSH2, MSH6 i PMS2. Ryzyko rozwoju raka jelita cienkiego u osób z zespołem Lyncha wynosi około 4%, co jest 100 razy wyższe niż w populacji ogólnej¹⁶¹⁷¹⁸.
Rodzinna polipowatość gruczolakowata (FAP) – związana z mutacją genu APC, powoduje rozwój setek lub tysięcy polipów w jelicie grubym, które mogą przekształcić się w nowotwór. U osób z FAP również w jelicie cienkim mogą rozwijać się polipy, szczególnie w dwunastnicy¹⁹²⁰.
Zespół Peutza-Jeghersa (PJS) – rzadki autosomalny dominujący zespół spowodowany mutacją w genie supresorowym guza STK11, który znacznie zwiększa ryzyko rozwoju raka jelita cienkiego²¹²².

Obecność predyspozycji genetycznej lub zespołu genetycznego występuje częściej w przypadku raka jelita cienkiego niż w przypadku raka jelita grubego i dotyczy około 20% przypadków w dużej kohorcie²³. Warto podkreślić, że osoby z tymi zespołami powinny być objęte specjalistycznym nadzorem onkologicznym.

Choroby zapalne jelit

Przewlekłe choroby zapalne jelit są istotnym czynnikiem ryzyka rozwoju raka jelita cienkiego:

Choroba Leśniowskiego-Crohna – charakteryzuje się przewlekłym zapaleniem błony śluzowej przewodu pokarmowego²⁴. Pacjenci z chorobą Crohna mają 8-krotnie zwiększone ryzyko rozwoju gruczolakoraka jelita cienkiego²⁵. Nowotwory związane z chorobą Crohna to zwykle gruczolakoraki jelita krętego. Tylko u około 2% osób z chorobą Crohna rozwinie się rak jelita cienkiego²⁶.
Celiakia – wiąże się z 10-krotnie zwiększonym ryzykiem raka jelita cienkiego w porównaniu do populacji ogólnej, jak wykazało szwedzkie badanie rejestrowe²⁷. Celiakia może nieznacznie zwiększać ryzyko rozwoju chłoniaka lub gruczolakoraka jelita cienkiego. Przestrzeganie diety bezglutenowej zmniejsza to ryzyko²⁸²⁹.

U osób z nieleczoną chorobą trzewną (celiakią) istnieje większe ryzyko rozwoju chłoniaka jelita cienkiego, szczególnie typu T-komórkowego związanego z enteropatią³⁰³¹.

Inne stany chorobowe

Oprócz chorób zapalnych jelit, istnieją inne stany chorobowe, które mogą zwiększać ryzyko raka jelita cienkiego:

Przebyte leczenie raka jelita grubego – osoby, które wcześniej miały raka jelita grubego, mają zwiększone ryzyko rozwoju raka jelita cienkiego. Może to wynikać z wspólnych czynników ryzyka³²³³.
Mukowiscydoza (CF) – osoby z tą chorobą mają zwiększone ryzyko raka jelita cienkiego³⁴³⁵.
Obniżona odporność – osoby z osłabionym układem odpornościowym, np. z zakażeniem HIV lub przyjmujące leki immunosupresyjne po przeszczepieniu narządów, mogą mieć zwiększone ryzyko raka jelita cienkiego³⁶.
Zakażenie Helicobacter pylori może być powiązane z podwyższonym ryzykiem raka jelita cienkiego³⁷³⁸.

Czynniki związane ze stylem życia, dietą i środowiskiem

Badania wskazują, że czynniki związane ze stylem życia, dietą oraz ekspozycją na czynniki środowiskowe mogą wpływać na ryzyko rozwoju raka jelita cienkiego. Chociaż nie wszystkie badania są jednoznaczne, zidentyfikowano kilka potencjalnych czynników ryzyka.

Czynniki dietetyczne

Dieta może odgrywać istotną rolę w rozwoju raka jelita cienkiego. Badania wykazały następujące powiązania:

Czerwone mięso – wysokie spożycie czerwonego mięsa może zwiększać ryzyko raka jelita cienkiego. Badanie z 1993 roku przeprowadzone przez Chow i wsp. wykazało, że podwyższone spożycie czerwonego mięsa 2-3-krotnie zwiększa ryzyko raka jelita cienkiego³⁹⁴⁰.
Produkty przetworzone – żywność peklowana lub wędzona również wiąże się ze zwiększonym ryzykiem⁴¹⁴².
Wysokotłuszczowa dieta – badanie z 1977 roku przeprowadzone przez Lowenfelsa i Sonniego wykazało korelację między spożyciem tłuszczów zwierzęcych a rakiem jelita cienkiego⁴³. Prospektywne badanie u ludzi wykazało wyraźnie podwyższone ryzyko guzów rakowiaka jelita cienkiego związane z dietą bogatą w tłuszcze nasycone⁴⁴.
Niska zawartość błonnika w diecie może zwiększać ryzyko⁴⁵.
Dieta bogata w cukier i produkty wysokoprzetworzone⁴⁶.

Warto zaznaczyć, że przestrzeganie diety bezglutenowej przez osoby z celiakią wydaje się zmniejszać ryzyko rozwoju raka jelita cienkiego⁴⁷.

Alkohol i palenie tytoniu

Badania dostarczają niejednoznacznych wyników odnośnie wpływu alkoholu i palenia tytoniu na ryzyko raka jelita cienkiego:

Alkohol – niektóre badania wykazały związek między spożyciem alkoholu a zwiększonym ryzykiem raka jelita cienkiego, ale nie wszystkie potwierdziły tę zależność⁴⁸⁴⁹.
Palenie tytoniu – podobnie jak w przypadku alkoholu, wyniki badań są niejednoznaczne. Niektóre badania wskazują na zwiększone ryzyko, inne nie potwierdzają tej zależności⁵⁰⁵¹.

Inne środowiskowe czynniki ryzyka

Do innych potencjalnych czynników ryzyka należą:

Narażenie na promieniowanie jonizujące – wcześniejsza radioterapia może zwiększać ryzyko rozwoju raka jelita cienkiego⁵²⁵³.
Narażenie zawodowe na pewne substancje chemiczne, takie jak kwas fenoksyoctowy⁵⁴.
Cholecystektomia (usunięcie pęcherzyka żółciowego) – zmienia przepływ żółci do jelita cienkiego, zwiększając ryzyko gruczolakoraków jelita cienkiego, przy czym ryzyko to maleje wraz ze zwiększaniem się odległości od przewodu żółciowego wspólnego⁵⁵.

Demograficzne czynniki ryzyka

Oprócz czynników genetycznych, środowiskowych i związanych ze stylem życia, istnieją również demograficzne czynniki ryzyka rozwoju raka jelita cienkiego.

Wiek, płeć i rasa

Rak jelita cienkiego częściej występuje w określonych grupach demograficznych:

Wiek – ryzyko raka jelita cienkiego wzrasta wraz z wiekiem. Większość przypadków jest diagnozowana u osób po 60. roku życia⁵⁶⁵⁷.
Płeć – rak jelita cienkiego występuje nieco częściej u mężczyzn niż u kobiet. Około 60% pacjentów stanowią mężczyźni⁵⁸⁵⁹.
Rasa – w Stanach Zjednoczonych osoby pochodzenia afroamerykańskiego są dotknięte tym nowotworem częściej niż osoby innych ras/grup etnicznych⁶⁰. Badania wykazały, że Afroamerykanie mają prawie dwukrotnie wyższą częstość występowania raków i guzów rakowiaka w porównaniu do osób rasy białej⁶¹.

Znaczące dysproporcje rasowe w występowaniu raka jelita cienkiego sugerują rolę czynników genetycznych, środowiskowych lub społeczno-ekonomicznych, które mogą przyczyniać się do tych różnic. Podobne dysproporcje obserwuje się w przypadku raka jelita grubego⁶²⁶³.

Prewencja i redukcja ryzyka

Ponieważ dokładna przyczyna raka jelita cienkiego nie jest znana, nie istnieje pewny sposób na jego zapobieganie⁶⁴. Istnieją jednak pewne strategie, które mogą pomóc w redukcji ryzyka, szczególnie dla osób ze zwiększonym ryzykiem rozwoju tego nowotworu.

Modyfikacje stylu życia

Zalecane modyfikacje stylu życia obejmują:

Zdrowa dieta – bogata w świeże owoce i warzywa, z ograniczeniem spożycia czerwonego mięsa, przetworzonego mięsa oraz tłuszczów zwierzęcych⁶⁵.
Utrzymywanie prawidłowej masy ciała – otyłość może być czynnikiem ryzyka⁶⁶.
Regularna aktywność fizyczna⁶⁷.
Ograniczenie spożycia alkoholu⁶⁸.
Rzucenie palenia⁶⁹.
Przestrzeganie diety bezglutenowej u osób z celiakią, co wydaje się zmniejszać ryzyko raka jelita cienkiego⁷⁰.

Monitoring i badania przesiewowe

Dla osób z podwyższonym ryzykiem rozwoju raka jelita cienkiego, szczególnie z predyspozycjami genetycznymi lub chorobami zapalnymi jelit, zaleca się:

Regularne badania przesiewowe – osoby z zespołami genetycznymi takimi jak zespół Lyncha, FAP czy zespół Peutza-Jeghersa powinny być objęte programem regularnych badań przesiewowych zgodnie z zaleceniami specjalistów⁷¹.
Monitorowanie i leczenie chorób zapalnych jelit – odpowiednie leczenie chorób takich jak choroba Leśniowskiego-Crohna czy celiakia może pomóc zmniejszyć ryzyko rozwoju raka⁷².
Usuwanie polipów – regularne badania w celu wykrycia i usunięcia polipów mogą zmniejszyć ryzyko transformacji nowotworowej⁷³.

Warto podkreślić, że nie istnieje obecnie powszechny program badań przesiewowych w kierunku raka jelita cienkiego dla osób bez czynników ryzyka, ze względu na rzadkość występowania tego nowotworu⁷⁴.

Aktualne badania i przyszłe kierunki

Badania nad rakiem jelita cienkiego są ograniczone ze względu na rzadkość występowania tego nowotworu i heterogenność typów guzów⁷⁵. Jednak trwające badania mogą przyczynić się do lepszego zrozumienia przyczyn i czynników ryzyka tego nowotworu.

Naukowcy badają interakcje między czynnikami genetycznymi, epigenetycznymi i środowiskowymi, które mogą przyczyniać się do rozwoju raka jelita cienkiego⁷⁶. Nowe kierunki badań obejmują rolę mikrobioty jelitowej, wpływ toksyn środowiskowych oraz identyfikację nowych markerów genetycznych ryzyka⁷⁷.

Lepsze zrozumienie mechanizmów molekularnych leżących u podstaw rozwoju raka jelita cienkiego może prowadzić do opracowania bardziej skutecznych strategii prewencji, wczesnego wykrywania i leczenia tego rzadkiego, ale poważnego nowotworu.

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Materiały źródłowe

#1 Small Intestine Cancer: Symptoms, Causes, Prognosis & Treatment
https://my.clevelandclinic.org/health/diseases/6225-small-intestine-cancer
Small intestine cancer is rare, making up only 3% of gastrointestinal cancers in the United States. […] What causes small intestine cancer? Malignant tumors form in your small intestine when cancer cells multiply rapidly, forming a mass. Over time, cancer cells may break away from the primary (original) tumor and travel through your lymph nodes or blood to other places in your body where another (secondary) tumor may form. This process is called metastasis. […] Cancer cells form because of genetic mutations, or changes in a cells DNA, that cause it to multiply out of control. Researchers dont know what causes these changes to occur. […] Some studies have suggested that diet (eating salty or smoked foods and red meat), tobacco use and alcohol consumption may play a role in small intestine cancer risk.
#2 Malignant Neoplasms of the Small Intestine: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/282684-overview
Malignant neoplasms of the small bowel are among the rarest types of cancer, accounting for 3.5% of all GI cancers. […] Research into the natural history and prognosis of patients with small bowel cancer has been limited by the small number of cases and the heterogeneity of tumor types: Small-bowel tumors may be adenocarcinomas, carcinoid tumors, lymphomas, sarcoma (most commonly leiomyosarcoma and more rarely angiosarcoma or liposarcoma), or gastrointestinal stromal tumors (GISTs). […] Each of these tumor subtypes has its own distinct clinical behavior and, therefore, requires a different treatment approach. […] People with familial adenomatous polyposis develop multiple adenomas throughout the small bowel and colon that may lead to adenocarcinomas. […] After the colon, the duodenum is the most common site of adenocarcinoma.
#3 Small bowel cancer – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/small-bowel-cancer/symptoms-causes/syc-20352497
The cause of small bowel cancer isn’t known. What’s known is that something happens to cells in the small bowel that changes them into cancer cells. […] Small bowel cancer happens when cells develop changes in their DNA. A cell’s DNA holds the instructions that tell the cell what to do. The changes tell the cells to multiply quickly. The cells continue living when healthy cells would die as part of their natural life cycle. This causes too many cells. The cells might form a mass called a tumor. The cells can invade and destroy healthy body tissue. In time, the cells can break away and spread to other parts of the body. […] Factors that may increase the risk of small bowel cancer include: DNA changes that run in families. Some DNA changes that are passed down from your parents can increase your risk of small bowel cancer and other cancers. Examples include Lynch syndrome, familial adenomatous polyposis, also called FAP, and Peutz-Jeghers syndrome.
#4 What Causes Small Intestine Cancer (Adenocarcinoma)? | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/what-causes.html
While there are several known risk factors for small intestine adenocarcinoma, not much is known about exactly what causes these cancers. […] Scientists have found some DNA changes inside small intestine adenocarcinoma cells that seem to help them grow and spread. […] Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes. […] For example, one cause of these cancers is thought to be problems with the tumor suppressor genes that normally help repair damaged DNA. […] Many small intestine cancers have specific known gene changes, but often its not clear what causes these changes. […] Gene changes inside cells can build up over a persons lifetime, which might help explain why small intestine cancer largely affects older people.
#5 Small Bowel Cancer – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK560725/
The basis for each malignancy is dependent on genetics and mutations that occur, resulting in malignant transformation of the cells. […] Longstanding celiac disease is an independent risk factor for the development of high-grade lymphomas of the small bowel. […] Most specifically, Crohn disease has been found to carry an increase in small bowel cancer. […] Cancer syndromes that carry an increased risk of cancer development in the colon can often carry an increased risk of cancer of the small bowel.
#6 Small Intestine Cancer: Symptoms, Causes, Prognosis & Treatment
https://my.clevelandclinic.org/health/diseases/6225-small-intestine-cancer
Small intestine cancer is rare, making up only 3% of gastrointestinal cancers in the United States. […] What causes small intestine cancer? Malignant tumors form in your small intestine when cancer cells multiply rapidly, forming a mass. Over time, cancer cells may break away from the primary (original) tumor and travel through your lymph nodes or blood to other places in your body where another (secondary) tumor may form. This process is called metastasis. […] Cancer cells form because of genetic mutations, or changes in a cells DNA, that cause it to multiply out of control. Researchers dont know what causes these changes to occur. […] Some studies have suggested that diet (eating salty or smoked foods and red meat), tobacco use and alcohol consumption may play a role in small intestine cancer risk.
#7 Small bowel cancer – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/small-bowel-cancer/symptoms-causes/syc-20352497
The cause of small bowel cancer isn’t known. What’s known is that something happens to cells in the small bowel that changes them into cancer cells. […] Small bowel cancer happens when cells develop changes in their DNA. A cell’s DNA holds the instructions that tell the cell what to do. The changes tell the cells to multiply quickly. The cells continue living when healthy cells would die as part of their natural life cycle. This causes too many cells. The cells might form a mass called a tumor. The cells can invade and destroy healthy body tissue. In time, the cells can break away and spread to other parts of the body. […] Factors that may increase the risk of small bowel cancer include: DNA changes that run in families. Some DNA changes that are passed down from your parents can increase your risk of small bowel cancer and other cancers. Examples include Lynch syndrome, familial adenomatous polyposis, also called FAP, and Peutz-Jeghers syndrome.
#8 What Causes Small Intestine Cancer (Adenocarcinoma)? | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/what-causes.html
While there are several known risk factors for small intestine adenocarcinoma, not much is known about exactly what causes these cancers. […] Scientists have found some DNA changes inside small intestine adenocarcinoma cells that seem to help them grow and spread. […] Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes. […] For example, one cause of these cancers is thought to be problems with the tumor suppressor genes that normally help repair damaged DNA. […] Many small intestine cancers have specific known gene changes, but often its not clear what causes these changes. […] Gene changes inside cells can build up over a persons lifetime, which might help explain why small intestine cancer largely affects older people.
#9 What Causes Small Intestine Cancer (Adenocarcinoma)? | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/what-causes.html
While there are several known risk factors for small intestine adenocarcinoma, not much is known about exactly what causes these cancers. […] Scientists have found some DNA changes inside small intestine adenocarcinoma cells that seem to help them grow and spread. […] Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes. […] For example, one cause of these cancers is thought to be problems with the tumor suppressor genes that normally help repair damaged DNA. […] Many small intestine cancers have specific known gene changes, but often its not clear what causes these changes. […] Gene changes inside cells can build up over a persons lifetime, which might help explain why small intestine cancer largely affects older people.
#10 What Causes Small Intestine Cancer (Adenocarcinoma)? | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/what-causes.html
While there are several known risk factors for small intestine adenocarcinoma, not much is known about exactly what causes these cancers. […] Scientists have found some DNA changes inside small intestine adenocarcinoma cells that seem to help them grow and spread. […] Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes. […] For example, one cause of these cancers is thought to be problems with the tumor suppressor genes that normally help repair damaged DNA. […] Many small intestine cancers have specific known gene changes, but often its not clear what causes these changes. […] Gene changes inside cells can build up over a persons lifetime, which might help explain why small intestine cancer largely affects older people.
#11 Small Intestine Cancer | Causes, Symptoms, & Treatment | MedStar Health
https://www.medstarhealth.org/services/small-intestine-cancer
Small intestine cancer, also called small bowel cancer, this is one of the most rare forms of GI cancer and can be challenging to detect. […] Many experts believe that cancer in the small intestine develops from a polyp that changes into cancer, much like colon cancer begins. […] Your diet and health history can increase your risk of developing small intestine cancer. […] A risk factor is something that increases your chances of developing a disease. Risk factors for small bowel cancer include: Eating a high-fat diet, Having Crohns disease, Having celiac disease, Having familial adenomatous polyposis (FAP). […] Because there’s no definitive cause of this type of cancer, there’s no way to guarantee prevention.
#12 Small intestine cancer | EBSCO Research Starters
https://www.ebsco.com/research-starters/health-and-medicine/small-intestine-cancer
The development of small intestine cancer is thought to be similar to the development of colorectal cancer. Like colorectal cancer, it begins as a (noncancerous) polyp (growth) on the wall of the intestine. Adenocarcinoma, for example, develops from glandular, fluid-secreting cells. Over time, changes occur in the cells in the polyp that cause it to become cancerous. Most small intestine cancer develops in the duodenum, the part of the small intestine closest to the stomach. In time, the polyps may grow to block the intestine.
#13 Tumors of the Small Intestine | MUSC Health | Charleston SC
https://muschealth.org/medical-services/ddc/patients/digestive-diseases/small-intestine/tumors-of-the-small-intestine
Adenocarcinoma of the small intestine probably develops mainly from adenomas. […] Other risk factors for adenocarcinoma include Crohn’s disease, celiac sprue, different types of previous surgery (i.e. surgery joining the urinary system with the intestines), and neurofibromatosis. […] Intestinal lymphoma of the small intestine is a recognized complication of celiac sprue, and can occur in immunodeficiency syndromes. […] Adenomas are benign tumors that do have malignant potential. […] Because of the risk of malignant degeneration, adenomas are usually removed (by surgery or endoscopy). […] Familial Adenomatous Polyposis are very strongly inherited (autosomal dominant). […] Over 80% of patients with these syndromes can also have adenomas involving the small intestine, which are also pre-malignant. […] There is a small risk of cancer, but far less than familial adenomatous polyposis. […] Generalized juvenile polyposis can be inherited or sporadic. […] There is a small increased risk of developing gastrointestinal cancer.
#14 Small Intestine Adenocarcinoma > Fact Sheets > Yale Medicine
https://www.yalemedicine.org/conditions/small-intestine-adenocarcinoma
Small intestine cancer is the umbrella term used for a number of different types of cancers that affect different parts of the small intestine. […] What causes small intestine adenocarcinoma? […] When certain cells within the small intestine mutate or change, they may begin to multiply uncontrollably, forming tumors or cancer. […] One theory on why this may happen is that chronic inflammation within the small intestine has been linked with mutation and excessive cell reproduction. Over time, inflammation is believed to cause changes to cells within the small intestine, leading the cells to mutate and multiply uncontrollably. […] Conditions like Crohns disease, ulcerative colitis, celiac disease, and other digestive conditions may cause chronic inflammation of the small intestine. It may also be caused by smoking and alcohol consumption, as well as by certain dietary habits, such as eating a lot of red meat or saturated fat.
#15 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Most cases of small bowel cancer are found in the duodenum. […] We dont know what causes most small bowel cancers. But there are some factors that may increase your risk. […] Age – small bowel cancer is more common in older people. […] Familial adenomatous polyposis a rare condition where an inherited faulty gene makes many polyps develop on the bowel lining. […] Lynch syndrome (Hereditary non polyposis colorectal cancer or HNPCC) – a gene fault that increases the risk of several different types of cancer at a younger age. […] Peutz Jeghers syndrome an inherited condition where benign (non cancerous) polyps form in the bowel. […] Crohns disease cancers related to Crohns disease are usually adenocarcinomas of the ileum. Only 2 out of 100 people with Crohn’s disease (2%) will develop cancer in the small bowel.
#16 Epidemiology, Risk Factors and Diagnosis of Small Bowel Adenocarcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC9103761/
Small bowel adenocarcinoma is a rare tumor. […] The most frequent primary location is the duodenum. […] There is no clearly identified environmental risk factor, but adenocarcinomas of the small intestine are associated in almost 20% of cases with predisposing diseases (Crohns disease, Lynch syndrome, familial adenomatous polyposis, PeutzJeghers syndrome and celiac disease). […] The presence of a predisposing disease or a genetic syndrome appears more frequently in SBA than in colorectal adenocarcinoma, and reached 20% in a large cohort. […] Lynch syndrome is a hereditary syndrome resulting from germline mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6 and PMS2). SBA is part of Lynch syndrome. […] Familial adenomatous polyposis (FAP) is related to mutation of the APC gene that results in numerous colon polyps and colorectal adenocarcinoma.
#17 Small Bowel Cancer: Alarming Symptoms and Causes, Types, Diagnosis and Treatment – OncoDaily
https://oncodaily.com/oncolibrary/cancer-types/small-bowel-cancer
Several factors contribute to the development of small bowel cancer: […] Conditions like Lynch syndrome and Familial Adenomatous Polyposis (FAP) significantly increase the risk. For instance, according to study by Koornstra et al published in Lancet in 2012, the risk of developing small-bowel cancer for a person with Lynch syndrome is around 4%, which is 100 times more compared with the general population. […] This inflammatory bowel disease is linked to a higher risk of small bowel cancer. According to ESMO reports patients with Crohns disease experienced an 8-fold increased risk of small bowel adenocarcinomas. […] High consumption of red meats and processed foods is associated with increased risk. […] Smoking, alcohol consumption, and obesity are potential contributors.
#18 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
In most cases, this disorder is caused by a defect in one of several mismatch repair (MMR) genes, such as MLH1, MSH2, MSH6, PMS1, or PMS2. Having an abnormal version of any one of these genes reduces the body’s ability to repair damage to its DNA. This results in an increased risk for cancer of the colon and small intestine, as well as a high risk of endometrial and ovarian cancer. […] People with this condition develop polyps in the stomach and intestines, as well as in other areas including the nose, the airways of the lungs, and the bladder. They can also have dark freckle-like spots on the lips, inner cheeks and other areas. PJS can increase the risk of many types of cancer, including small intestine adenocarcinoma. […] People with this syndrome develop colon polyps which will almost always become cancerous if the colon is not removed. They also can get polyps in the small intestine and have an increased risk of small intestine cancer. […] People with this condition have severe lung problems. Often, in someone with CF, the pancreas cannot make the enzymes that break food down so that it can be absorbed. People with CF have an increased risk of small intestine cancer.
#19 Epidemiology, Risk Factors and Diagnosis of Small Bowel Adenocarcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC9103761/
Small bowel adenocarcinoma is a rare tumor. […] The most frequent primary location is the duodenum. […] There is no clearly identified environmental risk factor, but adenocarcinomas of the small intestine are associated in almost 20% of cases with predisposing diseases (Crohns disease, Lynch syndrome, familial adenomatous polyposis, PeutzJeghers syndrome and celiac disease). […] The presence of a predisposing disease or a genetic syndrome appears more frequently in SBA than in colorectal adenocarcinoma, and reached 20% in a large cohort. […] Lynch syndrome is a hereditary syndrome resulting from germline mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6 and PMS2). SBA is part of Lynch syndrome. […] Familial adenomatous polyposis (FAP) is related to mutation of the APC gene that results in numerous colon polyps and colorectal adenocarcinoma.
#20 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
People who have had colon cancer have an increased risk of getting cancer of the small intestine. This could be due to shared risk factors. […] Crohn’s disease is a condition in which the immune system attacks the gastrointestinal (GI) tract. This disease can affect any part of the GI tract, but it most often affects the lower part of the small intestine. People with this condition have a much higher risk of small intestine cancer (particularly adenocarcinoma). These cancers are most often seen in the ileum (the last part of the small intestine, near the colon). […] People with certain inherited conditions have a higher risk of small intestine cancer (mainly adenocarcinoma). […] In this condition, many (often hundreds) of polyps develop in the colon and rectum. If the colon isn’t removed, one or more of these polyps will become cancerous. Polyps can also develop in the stomach and the small intestine, and they can lead to cancers in these areas. In FAP, most small intestine cancers are found in the duodenum.
#21 Epidemiology, Risk Factors and Diagnosis of Small Bowel Adenocarcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC9103761/
PeutzJeghers syndrome is a rare autosomal dominant syndrome caused by a mutation in the tumor suppressor gene STK11 which greatly increases the risk of developing SBA. […] Crohns disease is characterized by chronic inflammation of digestive tract mucosae. […] Celiac disease is associated with a relative risk of SBA compared to the general population which is estimated at 10 in a Swedish registry study.
#22 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Most cases of small bowel cancer are found in the duodenum. […] We dont know what causes most small bowel cancers. But there are some factors that may increase your risk. […] Age – small bowel cancer is more common in older people. […] Familial adenomatous polyposis a rare condition where an inherited faulty gene makes many polyps develop on the bowel lining. […] Lynch syndrome (Hereditary non polyposis colorectal cancer or HNPCC) – a gene fault that increases the risk of several different types of cancer at a younger age. […] Peutz Jeghers syndrome an inherited condition where benign (non cancerous) polyps form in the bowel. […] Crohns disease cancers related to Crohns disease are usually adenocarcinomas of the ileum. Only 2 out of 100 people with Crohn’s disease (2%) will develop cancer in the small bowel.
#23 Epidemiology, Risk Factors and Diagnosis of Small Bowel Adenocarcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC9103761/
Small bowel adenocarcinoma is a rare tumor. […] The most frequent primary location is the duodenum. […] There is no clearly identified environmental risk factor, but adenocarcinomas of the small intestine are associated in almost 20% of cases with predisposing diseases (Crohns disease, Lynch syndrome, familial adenomatous polyposis, PeutzJeghers syndrome and celiac disease). […] The presence of a predisposing disease or a genetic syndrome appears more frequently in SBA than in colorectal adenocarcinoma, and reached 20% in a large cohort. […] Lynch syndrome is a hereditary syndrome resulting from germline mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6 and PMS2). SBA is part of Lynch syndrome. […] Familial adenomatous polyposis (FAP) is related to mutation of the APC gene that results in numerous colon polyps and colorectal adenocarcinoma.
#24 Epidemiology, Risk Factors and Diagnosis of Small Bowel Adenocarcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC9103761/
PeutzJeghers syndrome is a rare autosomal dominant syndrome caused by a mutation in the tumor suppressor gene STK11 which greatly increases the risk of developing SBA. […] Crohns disease is characterized by chronic inflammation of digestive tract mucosae. […] Celiac disease is associated with a relative risk of SBA compared to the general population which is estimated at 10 in a Swedish registry study.
#25 Small Bowel Cancer: Alarming Symptoms and Causes, Types, Diagnosis and Treatment – OncoDaily
https://oncodaily.com/oncolibrary/cancer-types/small-bowel-cancer
Several factors contribute to the development of small bowel cancer: […] Conditions like Lynch syndrome and Familial Adenomatous Polyposis (FAP) significantly increase the risk. For instance, according to study by Koornstra et al published in Lancet in 2012, the risk of developing small-bowel cancer for a person with Lynch syndrome is around 4%, which is 100 times more compared with the general population. […] This inflammatory bowel disease is linked to a higher risk of small bowel cancer. According to ESMO reports patients with Crohns disease experienced an 8-fold increased risk of small bowel adenocarcinomas. […] High consumption of red meats and processed foods is associated with increased risk. […] Smoking, alcohol consumption, and obesity are potential contributors.
#26 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Most cases of small bowel cancer are found in the duodenum. […] We dont know what causes most small bowel cancers. But there are some factors that may increase your risk. […] Age – small bowel cancer is more common in older people. […] Familial adenomatous polyposis a rare condition where an inherited faulty gene makes many polyps develop on the bowel lining. […] Lynch syndrome (Hereditary non polyposis colorectal cancer or HNPCC) – a gene fault that increases the risk of several different types of cancer at a younger age. […] Peutz Jeghers syndrome an inherited condition where benign (non cancerous) polyps form in the bowel. […] Crohns disease cancers related to Crohns disease are usually adenocarcinomas of the ileum. Only 2 out of 100 people with Crohn’s disease (2%) will develop cancer in the small bowel.
#27 Epidemiology, Risk Factors and Diagnosis of Small Bowel Adenocarcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC9103761/
PeutzJeghers syndrome is a rare autosomal dominant syndrome caused by a mutation in the tumor suppressor gene STK11 which greatly increases the risk of developing SBA. […] Crohns disease is characterized by chronic inflammation of digestive tract mucosae. […] Celiac disease is associated with a relative risk of SBA compared to the general population which is estimated at 10 in a Swedish registry study.
#28 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Coeliac disease may slightly increase your risk of developing lymphoma or adenocarcinoma of the small bowel. Sticking to a gluten free diet reduces the risk. […] A diet rich in red meat or smoked foods, or a high fat diet. […] Smoking and drinking alcohol has also been linked to the risk of small bowel cancer, but we need further research to confirm this.
#29 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#30 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#31 Small-Intestine Cancer – Digestive Disorders – Merck Manual Consumer Version
https://www.merckmanuals.com/home/digestive-disorders/tumors-of-the-digestive-system/small-intestine-cancer
Cancer of the small intestine is uncommon in the United States, occurring in about 12,070 people and causing about 2,070 deaths each year. […] Adenocarcinoma is the most common type of cancer of the small intestine. Adenocarcinomas develop in the glandular cells of the lining of the small intestine. People with Crohn disease of the small intestine are more likely than others to develop adenocarcinoma. […] Lymphoma may develop in the middle section (jejunum) or the lower section (ileum) of the small intestine. This cancer is more common among people with untreated celiac disease. […] Adenocarcinoma may cause bleeding into the intestine, which shows up as blood in the stool, and obstruction, which in turn may lead to crampy abdominal pain, expansion (distention) of the abdomen, and vomiting. […] Sometimes cancers of the small intestine cause intussusception (when one part of the intestine telescopes into an adjacent part).
#32 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
People who have had colon cancer have an increased risk of getting cancer of the small intestine. This could be due to shared risk factors. […] Crohn’s disease is a condition in which the immune system attacks the gastrointestinal (GI) tract. This disease can affect any part of the GI tract, but it most often affects the lower part of the small intestine. People with this condition have a much higher risk of small intestine cancer (particularly adenocarcinoma). These cancers are most often seen in the ileum (the last part of the small intestine, near the colon). […] People with certain inherited conditions have a higher risk of small intestine cancer (mainly adenocarcinoma). […] In this condition, many (often hundreds) of polyps develop in the colon and rectum. If the colon isn’t removed, one or more of these polyps will become cancerous. Polyps can also develop in the stomach and the small intestine, and they can lead to cancers in these areas. In FAP, most small intestine cancers are found in the duodenum.
#33 Small bowel cancer | Macmillan Cancer Support
https://www.macmillan.org.uk/cancer-information-and-support/bowel-cancer/small-bowel-cancer
Doctors do not usually know what causes small bowel cancer. But research is being done to try to find out more. […] Some people with non-cancerous bowel conditions may have a higher risk of developing small bowel cancer. These conditions include: Crohns disease, coeliac disease, Peutz-Jeghers syndrome. […] People who have had colon cancer or rectal cancer have an increased risk of developing small bowel cancer. […] People also have a higher risk if they have: Lynch syndrome, also called hereditary non-polyposis colorectal cancer (HNPCC), familial adenomatous polyposis (FAP). […] Like all cancers, small bowel cancer is not infectious and cannot be passed to other people.
#34 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
In most cases, this disorder is caused by a defect in one of several mismatch repair (MMR) genes, such as MLH1, MSH2, MSH6, PMS1, or PMS2. Having an abnormal version of any one of these genes reduces the body’s ability to repair damage to its DNA. This results in an increased risk for cancer of the colon and small intestine, as well as a high risk of endometrial and ovarian cancer. […] People with this condition develop polyps in the stomach and intestines, as well as in other areas including the nose, the airways of the lungs, and the bladder. They can also have dark freckle-like spots on the lips, inner cheeks and other areas. PJS can increase the risk of many types of cancer, including small intestine adenocarcinoma. […] People with this syndrome develop colon polyps which will almost always become cancerous if the colon is not removed. They also can get polyps in the small intestine and have an increased risk of small intestine cancer. […] People with this condition have severe lung problems. Often, in someone with CF, the pancreas cannot make the enzymes that break food down so that it can be absorbed. People with CF have an increased risk of small intestine cancer.
#35
https://www.cancervic.org.au/cancer-information/types-of-cancer/small_bowel_cancer/small_bowel_overview.html
The cause of small bowel cancer is not known in most cases. However, there are several risk factors. Some small bowel cancers may be linked to Crohns disease and coeliac disease. Eating large amounts of animal fat and protein, especially processed meat and red meat, might also increase the risk. […] Some rare, inherited diseases can put people more at risk of small bowel cancer. These include familial adenomatous polyposis (FAP), Lynch syndrome (hereditary nonpolyposis colorectal cancer, or HNPCC), PeutzJeghers syndrome (PJS) and cystic fibrosis (CF). Multiple endocrine neoplasia (MEN 1) may increase the risk of small bowel neuroendocrine tumours.
#36 Small bowel cancer – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/small-bowel-cancer/symptoms-causes/syc-20352497
Other diseases and conditions that affect the intestines may increase the risk of small bowel cancer. These may include Crohn’s disease, inflammatory bowel disease and celiac disease. […] If your body’s germ-fighting immune system is weakened, you may have an increased risk of small bowel cancer. Examples include people with HIV infection and those who take medicine to control the immune system after an organ transplant. […] Some studies have found a higher risk of small bowel cancer in those who eat and drink certain things. For example, the risk seems to be associated with drinking alcohol and eating a diet that’s low in fiber and high in red meat, sugar, and salt-cured and smoked foods.
#37 Risks and causes of bowel cancer | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/bowel-cancer/risks-causes
People with type 2 diabetes have an increased risk of bowel cancer. […] People with acromegaly also have an increased risk of bowel cancer, although studies are still trying to find out why. […] Certain types of polyps called adenomas can develop into cancer over a long period of time. […] Around 2 in 100 (around 2%) of bowel cancers in the UK are linked to high energy (ionising) radiation exposure. […] There is some evidence that the risk of bowel cancer is higher in people who have an infection called Helicobacter pylori (H. pylori).
#38
http://www.bccancer.bc.ca/health-info/types-of-cancer/digestive-system/small-bowel
Small bowel cancer starts in the small intestine. The small intestine is the tube that connects your stomach to your large intestine. Most of your food is digested in your small intestine. […] Cancer of the small bowel is rare. About 60% (60 out of 100) of people who get small intestine cancer are men. […] These are some of the risk factors for this cancer. Not all of these risk factors may cause this cancer, but they may help the cancer start growing. […] Being over the age of 45. […] Eating large amounts of: […] Animal proteins and animal fat. […] Refined carbohydrates. […] Red meat. […] Salt-cured or smoked foods. […] An infection with Helicobacter pylori. […] Having Crohn’s Disease or Celiac Disease. […] Radiation therapy for cancer of the cervix. […] People with inherited disorders such as:
#39 Malignant Neoplasms of the Small Intestine: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/282684-overview
A 1993 study from Johns Hopkins by Offerhaus et al found that patients with familial adenomatous polyposis have a relative risk of more than 300 for duodenal adenocarcinoma but no elevated risk for gastric or nonduodenal small-bowel cancer. […] People with hereditary nonpolyposis colorectal cancer (HNPCC) not only develop colorectal carcinoma, but also endometrial, gastric, small bowel, upper urinary tract, and ovarian carcinomas. […] The lifetime risk of small-bowel adenocarcinoma in people with HNPCC is 1-4%, which is more than 100 times the risk in the general population. […] A 1977 study by Lowenfels and Sonni found animal fat intake to be correlated with small-bowel cancer. […] Another study, in 1993 by Chow et al, reported that elevated consumption of red meat and salt-cured or smoked foods raised the risk of small-bowel cancer 2-3 times.
#40 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#41 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#42
https://link.springer.com/article/10.1007/BF00053158
Small intestine cancer is relatively rare. Clinical reports have suggested that several medical conditions may predispose to increased occurrence of this cancer, but otherwise its etiology is unknown. […] Tobacco and alcohol consumption were unrelated to risk of small intestine cancer, but weekly or more frequent consumption of red meat and monthly or more frequent intake of salt-cured/smoked foods were associated with two-to three fold increases in risk. The findings suggest that dietary factors probably are involved in risk of small intestine cancer, but additional research in other settings is required to clarify the determinants of these rare cancers.
#43 Malignant Neoplasms of the Small Intestine: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/282684-overview
A 1993 study from Johns Hopkins by Offerhaus et al found that patients with familial adenomatous polyposis have a relative risk of more than 300 for duodenal adenocarcinoma but no elevated risk for gastric or nonduodenal small-bowel cancer. […] People with hereditary nonpolyposis colorectal cancer (HNPCC) not only develop colorectal carcinoma, but also endometrial, gastric, small bowel, upper urinary tract, and ovarian carcinomas. […] The lifetime risk of small-bowel adenocarcinoma in people with HNPCC is 1-4%, which is more than 100 times the risk in the general population. […] A 1977 study by Lowenfels and Sonni found animal fat intake to be correlated with small-bowel cancer. […] Another study, in 1993 by Chow et al, reported that elevated consumption of red meat and salt-cured or smoked foods raised the risk of small-bowel cancer 2-3 times.
#44 Small intestine cancer – Wikipedia
https://en.wikipedia.org/wiki/Small_intestine_cancer
Small intestine cancer can be subdivided into duodenal cancer (the first part of the small intestine) and cancer of the jejunum and ileum (the latter two parts of the small intestine). […] Experts believe that small intestine cancer develops much like colorectal cancer. It first begins as a small growth on the inner lining of the intestine (polyp), which over time becomes cancer. […] Risk factors for small intestine cancer include: Age: Cancer risk increases with age. The average age diagnosis is 65. […] Diet: Various research has suggested that diets high in red meat and salted or smoked foods may raise the risk of small intestine cancer. A human prospective study observed a markedly elevated risk for carcinoid tumors of the small intestine associated with dietary intake of saturated fat. […] Cholecystectomy, which alters the flow of bile to the small intestine, increases the risk of small intestinal adenocarcinomas, and this risk declines with increasing distance from the common bile duct.
#45 Small bowel cancer – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/small-bowel-cancer/symptoms-causes/syc-20352497
Other diseases and conditions that affect the intestines may increase the risk of small bowel cancer. These may include Crohn’s disease, inflammatory bowel disease and celiac disease. […] If your body’s germ-fighting immune system is weakened, you may have an increased risk of small bowel cancer. Examples include people with HIV infection and those who take medicine to control the immune system after an organ transplant. […] Some studies have found a higher risk of small bowel cancer in those who eat and drink certain things. For example, the risk seems to be associated with drinking alcohol and eating a diet that’s low in fiber and high in red meat, sugar, and salt-cured and smoked foods.
#46 Small Intestine Adenocarcinoma > Fact Sheets > Yale Medicine
https://www.yalemedicine.org/conditions/small-intestine-adenocarcinoma
People may be at higher risk if they have, or have had, these medical conditions: Crohns disease, Celiac disease, Peptic ulcers, Colorectal cancer, A family history of conditions that raise the risk of intestinal cancer, including familial adenomatous polyposis, Lynch syndrome, and Peutz-Jeghers syndrome, Cystic fibrosis, HIV or AIDS, An organ transplant, Previous radiation therapy, Surgery to remove the gallbladder. […] Additionally, eating the following types of food may raise a persons risk of small intestine adenocarcinoma: Red meat, Smoked meat, Salt-cured meat, Saturated fat, Sugar. […] Consuming alcoholic beverages and smoking cigarettes are additional habits linked to small intestine cancer.
#47
http://www.bccancer.bc.ca/health-info/types-of-cancer/digestive-system/small-bowel
Familial Adenomatous Polyposis (FAP) […] Hereditary Nonpolyposis Colorectal Cancer (HNPCC) […] Peutz-Jeghers Syndrome (PJS) […] Cystic Fibrosis (CF). […] Eating healthy, nutritious foods can lower your cancer risk. […] Eat a gluten-free diet if you have celiac disease. This seems to lower the risk of small bowel cancer. […] There is no screening program for small bowel cancer.
#48 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#49 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Coeliac disease may slightly increase your risk of developing lymphoma or adenocarcinoma of the small bowel. Sticking to a gluten free diet reduces the risk. […] A diet rich in red meat or smoked foods, or a high fat diet. […] Smoking and drinking alcohol has also been linked to the risk of small bowel cancer, but we need further research to confirm this.
#50 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#51
https://link.springer.com/article/10.1007/BF00053158
Small intestine cancer is relatively rare. Clinical reports have suggested that several medical conditions may predispose to increased occurrence of this cancer, but otherwise its etiology is unknown. […] Tobacco and alcohol consumption were unrelated to risk of small intestine cancer, but weekly or more frequent consumption of red meat and monthly or more frequent intake of salt-cured/smoked foods were associated with two-to three fold increases in risk. The findings suggest that dietary factors probably are involved in risk of small intestine cancer, but additional research in other settings is required to clarify the determinants of these rare cancers.
#52 Risks and causes of bowel cancer | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/bowel-cancer/risks-causes
People with type 2 diabetes have an increased risk of bowel cancer. […] People with acromegaly also have an increased risk of bowel cancer, although studies are still trying to find out why. […] Certain types of polyps called adenomas can develop into cancer over a long period of time. […] Around 2 in 100 (around 2%) of bowel cancers in the UK are linked to high energy (ionising) radiation exposure. […] There is some evidence that the risk of bowel cancer is higher in people who have an infection called Helicobacter pylori (H. pylori).
#53 Small Intestine Adenocarcinoma > Fact Sheets > Yale Medicine
https://www.yalemedicine.org/conditions/small-intestine-adenocarcinoma
People may be at higher risk if they have, or have had, these medical conditions: Crohns disease, Celiac disease, Peptic ulcers, Colorectal cancer, A family history of conditions that raise the risk of intestinal cancer, including familial adenomatous polyposis, Lynch syndrome, and Peutz-Jeghers syndrome, Cystic fibrosis, HIV or AIDS, An organ transplant, Previous radiation therapy, Surgery to remove the gallbladder. […] Additionally, eating the following types of food may raise a persons risk of small intestine adenocarcinoma: Red meat, Smoked meat, Salt-cured meat, Saturated fat, Sugar. […] Consuming alcoholic beverages and smoking cigarettes are additional habits linked to small intestine cancer.
#54 Cancer of Small Intestine: Symptoms, Causes, Diagnosis, Treatment
https://www.webmd.com/cancer/cancer-of-the-small-intestine
Doctors arent really sure why people develop it. But they do know that several things can increase your chances of getting the disease: […] How old you are (average age at diagnosis is 60) […] Your sex (slightly higher risk in men) […] Genetics (some disorders youre born with raise the odds) […] Smoking and alcohol use […] High-fat diet […] Living or working near large quantities of some chemicals, like phenoxyacetic acid […] Other conditions that affect your gut, like Crohns, colon cancer, or celiac disease […] Lymphedema (damage to the vessels that connect to the lymph nodes)
#55 Small intestine cancer – Wikipedia
https://en.wikipedia.org/wiki/Small_intestine_cancer
Small intestine cancer can be subdivided into duodenal cancer (the first part of the small intestine) and cancer of the jejunum and ileum (the latter two parts of the small intestine). […] Experts believe that small intestine cancer develops much like colorectal cancer. It first begins as a small growth on the inner lining of the intestine (polyp), which over time becomes cancer. […] Risk factors for small intestine cancer include: Age: Cancer risk increases with age. The average age diagnosis is 65. […] Diet: Various research has suggested that diets high in red meat and salted or smoked foods may raise the risk of small intestine cancer. A human prospective study observed a markedly elevated risk for carcinoid tumors of the small intestine associated with dietary intake of saturated fat. […] Cholecystectomy, which alters the flow of bile to the small intestine, increases the risk of small intestinal adenocarcinomas, and this risk declines with increasing distance from the common bile duct.
#56 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#57 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Most cases of small bowel cancer are found in the duodenum. […] We dont know what causes most small bowel cancers. But there are some factors that may increase your risk. […] Age – small bowel cancer is more common in older people. […] Familial adenomatous polyposis a rare condition where an inherited faulty gene makes many polyps develop on the bowel lining. […] Lynch syndrome (Hereditary non polyposis colorectal cancer or HNPCC) – a gene fault that increases the risk of several different types of cancer at a younger age. […] Peutz Jeghers syndrome an inherited condition where benign (non cancerous) polyps form in the bowel. […] Crohns disease cancers related to Crohns disease are usually adenocarcinomas of the ileum. Only 2 out of 100 people with Crohn’s disease (2%) will develop cancer in the small bowel.
#58
http://www.bccancer.bc.ca/health-info/types-of-cancer/digestive-system/small-bowel
Small bowel cancer starts in the small intestine. The small intestine is the tube that connects your stomach to your large intestine. Most of your food is digested in your small intestine. […] Cancer of the small bowel is rare. About 60% (60 out of 100) of people who get small intestine cancer are men. […] These are some of the risk factors for this cancer. Not all of these risk factors may cause this cancer, but they may help the cancer start growing. […] Being over the age of 45. […] Eating large amounts of: […] Animal proteins and animal fat. […] Refined carbohydrates. […] Red meat. […] Salt-cured or smoked foods. […] An infection with Helicobacter pylori. […] Having Crohn’s Disease or Celiac Disease. […] Radiation therapy for cancer of the cervix. […] People with inherited disorders such as:
#59 Digestive & Bowel Cancer Facts & Symptoms | UHC Oncology
https://wvcancercenter.com/specific-cancers/digestive-bowel-cancer-facts/
The small intestines are often referred to as the small bowel. Small intestine cancer is slightly more common in men than women. Diet and health history are risk factors. […] Common Causes of Stomach Cancer: Infection from H. pylori bacteria, Age, Diet. […] Early causes can begin in noncancerous polyps, which may cause symptoms, but can be better detected by screenings.
#60 Risk Factors for Small Intestine Cancer (Adenocarcinoma) | American Cancer Society
https://www.cancer.org/cancer/types/small-intestine-cancer/causes-risks-prevention/risk-factors.html
Small intestine cancer occurs slightly more often in men than in women. […] Cancers of the small intestine tend to occur more often in older people. They are most often found in people in their 60s and 70s. […] In the United States, African Americans are affected more often by these cancers than people of other races/ethnicities. […] Some studies have found an increased risk with either smoking or drinking alcohol, but not all studies have found this. […] Some research has suggested that diets high in red meat and salted or smoked foods might raise the risk of small intestine cancer. […] For people with celiac disease, eating gluten (a protein that is found in wheat and some other types of grain) causes the body’s immune system to attack the lining of the intestines. People with celiac disease have an increased risk of a certain kind of lymphoma of the intestine called enteropathy-associated T-cell lymphoma. They may also have an increased risk of small intestine cancer.
#61
https://link.springer.com/article/10.1007/s10552-005-3635-6
Men had higher rates than women for all types of small bowel cancer. […] Blacks had almost double the incidence of carcinomas and carcinoid tumors compared to whites (10.6 vs. 5.6 per million people; 9.2 vs. 5.4 per million people, respectively). […] Small bowel cancer incidence in the U.S. is higher in blacks compared to whites, particularly for carcinomas and carcinoid tumors. Small bowel cancer incidence is rising, particularly in black men. The geographic correlation between large and small bowel cancer suggests shared etiologies.
#62 Colorectal cancer: Symptoms, stages, & outlook
https://www.medicalnewstoday.com/articles/155598
The cause of colorectal cancer is unclear, but it likely stems from a combination of genetic and environmental factors. […] Around 70% of colon cancer cases have no apparent cause. Inherited colon cancer-related genetic mutations may account for 3% to 5% of cases. Between 20% and 25% of people may have a family history of the condition but no inherited mutations. […] Some other colorectal cancer risk factors may include: being over the age of 50, being male, a diet high in red or processed meats, consuming alcohol, smoking, low levels of physical activity, overweight or obesity, IBD, type 2 diabetes, having undergone radiation therapy for abdominal cancer in childhood, polyps in the colon or rectum. […] According to a 2023 review, Black Americans and Alaskan Native people are more likely to develop and die from colorectal cancer than any other group of people in the U.S.
#63 Colorectal cancer: Symptoms, stages, & outlook
https://www.medicalnewstoday.com/articles/155598
The ACS states the chance of having this type of cancer is at least 20% higher for African Americans than for white people, and the fatality rate is 40% higher for African Americans. […] This may be due to socioeconomic factors and inequity in screening and other aspects of healthcare, as well as inequity in employment, diet, and other factors related to daily life.
#64 Small Intestine Cancer | Causes, Symptoms, & Treatment | MedStar Health
https://www.medstarhealth.org/services/small-intestine-cancer
Small intestine cancer, also called small bowel cancer, this is one of the most rare forms of GI cancer and can be challenging to detect. […] Many experts believe that cancer in the small intestine develops from a polyp that changes into cancer, much like colon cancer begins. […] Your diet and health history can increase your risk of developing small intestine cancer. […] A risk factor is something that increases your chances of developing a disease. Risk factors for small bowel cancer include: Eating a high-fat diet, Having Crohns disease, Having celiac disease, Having familial adenomatous polyposis (FAP). […] Because there’s no definitive cause of this type of cancer, there’s no way to guarantee prevention.
#65 Bowel cancer | Causes, Symptoms & Treatments | Cancer Council
https://www.cancer.org.au/cancer-information/types-of-cancer/bowel-cancer
Some factors that increase your risk of bowel cancer include: […] Cancer can also start in the small bowel but this is a rare cancer. […] The risk of bowel cancer can be reduced by a healthy diet with plenty of fresh fruit and vegetables, limiting consumption of red meat, avoiding processed meats, not smoking, limiting alcohol consumption, being physically active, and maintaining a healthy body weight.
#66 Bowel cancer | Causes, Symptoms & Treatments | Cancer Council
https://www.cancer.org.au/cancer-information/types-of-cancer/bowel-cancer
Some factors that increase your risk of bowel cancer include: […] Cancer can also start in the small bowel but this is a rare cancer. […] The risk of bowel cancer can be reduced by a healthy diet with plenty of fresh fruit and vegetables, limiting consumption of red meat, avoiding processed meats, not smoking, limiting alcohol consumption, being physically active, and maintaining a healthy body weight.
#67 Bowel cancer | Causes, Symptoms & Treatments | Cancer Council
https://www.cancer.org.au/cancer-information/types-of-cancer/bowel-cancer
Some factors that increase your risk of bowel cancer include: […] Cancer can also start in the small bowel but this is a rare cancer. […] The risk of bowel cancer can be reduced by a healthy diet with plenty of fresh fruit and vegetables, limiting consumption of red meat, avoiding processed meats, not smoking, limiting alcohol consumption, being physically active, and maintaining a healthy body weight.
#68 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Coeliac disease may slightly increase your risk of developing lymphoma or adenocarcinoma of the small bowel. Sticking to a gluten free diet reduces the risk. […] A diet rich in red meat or smoked foods, or a high fat diet. […] Smoking and drinking alcohol has also been linked to the risk of small bowel cancer, but we need further research to confirm this.
#69 What is small bowel cancer? | Cancer Research UK
https://www.cancerresearchuk.org/about-cancer/small-bowel-cancer/about
Coeliac disease may slightly increase your risk of developing lymphoma or adenocarcinoma of the small bowel. Sticking to a gluten free diet reduces the risk. […] A diet rich in red meat or smoked foods, or a high fat diet. […] Smoking and drinking alcohol has also been linked to the risk of small bowel cancer, but we need further research to confirm this.
#70
http://www.bccancer.bc.ca/health-info/types-of-cancer/digestive-system/small-bowel
Familial Adenomatous Polyposis (FAP) […] Hereditary Nonpolyposis Colorectal Cancer (HNPCC) […] Peutz-Jeghers Syndrome (PJS) […] Cystic Fibrosis (CF). […] Eating healthy, nutritious foods can lower your cancer risk. […] Eat a gluten-free diet if you have celiac disease. This seems to lower the risk of small bowel cancer. […] There is no screening program for small bowel cancer.
#71 Diagnosing Small Intestine Cancer | NYU Langone Health
https://nyulangone.org/conditions/small-intestine-cancer/diagnosis
Several types of cancer can arise in the small intestine. Adenocarcinoma is the most common. It develops from gland cells that line the intestine and secrete the fluid that aids digestion. Other types of small intestine cancer include carcinoids, which are a form of gastrointestinal neuroendocrine tumors, lymphoma, and sarcoma. […] Crohns disease, which is chronic inflammation in the digestive tract, can lead to an increased risk of developing small intestine cancer. […] People with certain hereditary genetic cancer syndromes are also at increased risk. These syndromes cause noncancerous growths called polyps to develop in the small intestine and other organs of the digestive tract. Polyps can eventually become cancerous. These hereditary syndromes include Lynch syndrome, familial adenomatous polyposis, which is also called FAP, and PeutzJeghers syndrome. NYU Langone specialists carefully monitor people with these genetic conditions for the development of small intestine tumors and other cancers of the digestive system.
#72 Small Intestine Cancer : Symptoms, Signs and Causes | HCG
https://www.hcgoncology.com/types-of-cancers/small-intestine-cancer-symptoms-and-causes/
Small intestine cancer can disrupt normal digestive processes, leading to symptoms like nausea, diarrhea, or vomiting. Persistent gastrointestinal issues could be one of the small intestine cancer signs. […] Chronic inflammation of the small intestine, often associated with conditions like Crohn’s disease or celiac disease, may be one of the potential small intestine cancer causes. Regular monitoring and management of inflammatory bowel conditions are essential preventive measures. […] The presence of polyps in the small intestine could also be one of the possible small intestine cancer causes. Regular screenings to detect and remove polyps can reduce the risk of malignant transformation. […] Engaging in tobacco and alcohol use may be one of the potential small intestine cancer causes. Adopting lifestyle changes, such as quitting smoking and moderating alcohol consumption, can positively impact overall health.
#73 Small Intestine Cancer : Symptoms, Signs and Causes | HCG
https://www.hcgoncology.com/types-of-cancers/small-intestine-cancer-symptoms-and-causes/
Small intestine cancer can disrupt normal digestive processes, leading to symptoms like nausea, diarrhea, or vomiting. Persistent gastrointestinal issues could be one of the small intestine cancer signs. […] Chronic inflammation of the small intestine, often associated with conditions like Crohn’s disease or celiac disease, may be one of the potential small intestine cancer causes. Regular monitoring and management of inflammatory bowel conditions are essential preventive measures. […] The presence of polyps in the small intestine could also be one of the possible small intestine cancer causes. Regular screenings to detect and remove polyps can reduce the risk of malignant transformation. […] Engaging in tobacco and alcohol use may be one of the potential small intestine cancer causes. Adopting lifestyle changes, such as quitting smoking and moderating alcohol consumption, can positively impact overall health.
#74
http://www.bccancer.bc.ca/health-info/types-of-cancer/digestive-system/small-bowel
Familial Adenomatous Polyposis (FAP) […] Hereditary Nonpolyposis Colorectal Cancer (HNPCC) […] Peutz-Jeghers Syndrome (PJS) […] Cystic Fibrosis (CF). […] Eating healthy, nutritious foods can lower your cancer risk. […] Eat a gluten-free diet if you have celiac disease. This seems to lower the risk of small bowel cancer. […] There is no screening program for small bowel cancer.
#75 Malignant Neoplasms of the Small Intestine: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/282684-overview
Malignant neoplasms of the small bowel are among the rarest types of cancer, accounting for 3.5% of all GI cancers. […] Research into the natural history and prognosis of patients with small bowel cancer has been limited by the small number of cases and the heterogeneity of tumor types: Small-bowel tumors may be adenocarcinomas, carcinoid tumors, lymphomas, sarcoma (most commonly leiomyosarcoma and more rarely angiosarcoma or liposarcoma), or gastrointestinal stromal tumors (GISTs). […] Each of these tumor subtypes has its own distinct clinical behavior and, therefore, requires a different treatment approach. […] People with familial adenomatous polyposis develop multiple adenomas throughout the small bowel and colon that may lead to adenocarcinomas. […] After the colon, the duodenum is the most common site of adenocarcinoma.
#76 Colorectal Cancer Rising among Young Adults – NCI
https://www.cancer.gov/news-events/cancer-currents-blog/2020/colorectal-cancer-rising-younger-adults
Scientists are also examining factors in the environment as potential causes of early-onset colorectal cancer. […] The National Toxicology Program, led by NIEHS, has identified 18 chemicals that cause cancer in the intestines of mice or rats, said NIEHS Director Rick Woychik, Ph.D., who also heads the National Toxicology Program. […] Some of these chemicals might damage DNA, potentially leading to harmful mutations in cells of the colon and rectum. […] Other chemicals may have more indirect effects, pointed out Barbara Cohn, Ph.D., M.P.H. of the Public Health Institute. […] Even though some of those chemicals are now banned, their use in earlier decades could have effects later in life for people who were born back then, Dr. Cohn explained. […] How those chemicals interact with a persons genetic and epigenetic characteristics is also important, he added.
#77 Colorectal Cancer Rising among Young Adults – NCI
https://www.cancer.gov/news-events/cancer-currents-blog/2020/colorectal-cancer-rising-younger-adults
When the incidence of a disease changes by generation, that suggests the culprit is something in the environment, rather than something biological, Dr. Ng added, with many other meeting participants agreeing. […] Theres mounting evidence linking an unhealthy dietin particular, one high in processed meat and fat, and low in fruits and vegetablesto early-onset colorectal cancer. […] Likewise, several studies have found that being overweight or obese may raise someones chance of getting early-onset colorectal cancer. […] In addition, Americans are spending more time sitting and less time being active. […] Other scientists have turned their focus to bacteria that live in the gut, also called the gut microbiome. […] Changes in the gut microbiome may be influencing the increasing rates of colorectal cancer in adults under 50.