Small intestine cancer
Small intestine cancer, also known as small bowel cancer or small bowel neoplasm, is a rare form of cancer that originates in the small intestine, the section of the digestive system situated between the stomach and colon. It is most commonly represented by adenocarcinoma, accounting for 30 to 40 percent of cases, but can also include sarcoma, carcinoid tumors, gastrointestinal stromal tumors (GIST), and lymphoma. Risk factors for developing this cancer include conditions like Crohn's disease, cystic fibrosis, and celiac disease, along with genetic syndromes such as familial adenomatous polyposis and Peutz-Jeghers syndrome.
Symptoms in the early stages are often nonspecific, but may progress to include weight loss, abdominal pain, and blood in the stool. Diagnosis typically involves a combination of physical examinations, imaging studies, and biopsies. Treatment usually requires surgical intervention to remove the affected bowel segment, often followed by chemotherapy or radiation therapy. Despite advancements in treatment options, including immunotherapy, the prognosis remains challenging, particularly because the cancer is often diagnosed at an advanced stage. The five-year survival rates vary significantly based on the stage at diagnosis, highlighting the importance of awareness and understanding of this rare cancer.
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Small intestine cancer
ALSO KNOWN AS: Small bowel cancer, small bowel neoplasm, small intestine adenocarcinoma
RELATED CONDITIONS: Familial adenomatous polyposis
DEFINITION: Small intestine cancer is a primary cancer that arises in the small intestine (small bowel), the part of the digestive system that connects the stomach and the colon.
Risk factors: Small intestine cancer is more likely to occur in individuals who have Crohn's disease, cystic fibrosis, or celiac disease. Individuals who have the genetic conditions familiar adenomatous polyposis (FAP), nonpolyposis cancer, and Peutz-Jeghers syndrome also have a higher risk of developing small intestine cancer. Tobacco and alcohol use and a diet heavy in animal fats have been found to increase small intestine cancer in some, but not all, studies. Age and race may also play a role, as adults in their sixties and seventies and Black Americans have a higher incidence of small intestine cancer.
Etiology and the disease process: There are five kinds of small intestine cancer: adenocarcinoma, sarcoma, carcinoid tumors, gastrointestinal stromal tumors (GIST), and lymphoma. These cancers arise from different cell types. Adenocarcinoma is the most common type of small intestine cancer, making up between 30 and 40 percent of all diagnosed cases, according to the Cleveland Clinic.
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.
Incidence: Small intestine cancer is rare. According to the Cleveland Clinic, it accounts for only 2 to 3 percent of all cancers of the gastrointestinal system. The American Cancer Society estimates that in 2023 about 12,070 new cases were diagnosed in the United States and that about 2,090 people died from the disease. This cancer is slightly more common in men than in women and in Black Americans than in Whites. The average age at diagnosis is between sixty and seventy. Internationally, small intestine cancer is more common in the United States and Western Europe and less common in Asia.
Symptoms: In its early stages, small intestine cancer causes few signs. In later stages, possible signs include unexplained weight loss, abdominal cramps or pain, a lump in the abdomen, or blood in the stool. These symptoms are general and may be caused by many other diseases and conditions.
Screening and diagnosis: Because of the rarity of small intestine cancer, routine screening is not done. Because symptoms are general, diagnosis requires an extensive series of tests. These include a physical examination, blood work, liver function tests, and a fecal occult blood test to test for blood in the stool. Imaging studies may include abdominal X-rays, an upper gastrointestinal endoscopy, a barium enema and lower gastrointestinal X-rays, and a computed tomography (CT) scan. Endoscopic technologies have improved diagnostic times as well. A definitive diagnosis comes from a of polyps in the intestine.
To stage the cancer, a laparotomy may be performed. In this surgical procedure, the abdomen is opened, and samples are taken to determine how far the cancer has spread. Likewise, a lymph node biopsy may also be done to determine how far the cancer has spread.
Staging is done based on the degree of invasiveness of the tumor, how far the cancer has spread, and whether it can be entirely removed with surgery:
- Stage I: The tumor is localized and has invaded the intestinal wall only to a limited degree.
- Stage II: The cancer has grown through the intestinal wall but has not spread to the surrounding lymph nodes.
- Stage III: The cancer has spread to the lymph nodes.
- Stage IV: The tumor has spread to distant organs, such as the lung or liver.
Treatment and therapy: The preferred treatment for all small intestine cancer is surgical removal of the diseased portion of the bowel. Minimally invasive surgical techniques have improved outcomes for patients with small intestine cancer. This is usually followed by chemotherapy, radiation therapy, or both. Immunotherapy has emerged as a promising treatment for small intestine cancer. When the cancer cannot be removed, palliative care includes surgery to bypass any portions of the small bowel that are blocked by polyp growth.
Prognosis, prevention, and outcomes: Small intestine cancer is difficult to successfully treat because it is rarely diagnosed at an early stage. The American Cancer Society estimates the five-year survival rate for people with small intestine adenocarcinoma is 84 percent when the cancer is localized to the small intestine, 78 percent when the cancer is regional (stages II and III), and 42 percent when the cancer has spread to other distant parts of the body.
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