Small intestine cancer is one of the rarest types of cancer affecting your gastrointestinal tract. Different types include carcinoid tumors, adenocarcinomas, sarcomas and lymphoma. Diagnosis often requires multiple procedures and tests. Your prognosis depends on numerous factors, including the cancer type, its stage and where the tumor started in your small intestine.
Small intestine cancer happens when malignant (cancer) cells form in your small intestine, or small bowel. Your small intestine is part of your body’s digestive system, which includes organs like your liver, pancreas and gallbladder, as well as your gastrointestinal (GI) tract. Your small intestine is part of your GI tract, a pathway of organs that includes your esophagus, stomach, small intestine and large intestine (colon). Your small intestine connects your stomach to your large intestine.
Your small intestine consists of three parts:
Most small intestine cancer forms in either your duodenum or ileum.
Small intestine cancer is rare, making up only 3% of gastrointestinal cancers in the United States. Colon cancer, rectal cancer, esophageal cancer and stomach cancer are more common than cancer affecting your small intestine.
The different types of small intestine cancer are classified based on the type of cells where the cancer starts.
The symptoms of small intestine cancer vary depending on the type of tumor and where it’s located. Sometimes, tumors are asymptomatic, which means they don’t cause symptoms. For example, carcinoid tumors often don’t cause symptoms. They may only be found incidentally during an imaging procedure for an unrelated issue.
Symptoms may include:
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 cell’s DNA, that cause it to multiply out of control. Researchers don’t know what causes these changes to occur.
A risk factor includes anything that increases your chances of getting a disease. Having a risk factor doesn’t mean you’ll get cancer. Not having risk factors doesn’t mean you won’t get cancer.
Risk factors for small intestine cancer include:
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.
Talk to your healthcare provider if you’re concerned you may be at risk for small intestine cancer.
Small intestine cancer can be challenging to diagnose because it’s so rare. Also, symptoms vary depending on the type of tumor. It may take extensive procedures and tests before you receive a diagnosis.
Your healthcare provider will examine you to check your general health and look for signs of disease. They’ll take a history of past illnesses and treatments and ask about your health habits.
Your healthcare provider may perform surgery if other tests don’t provide enough information for a diagnosis. These procedures allow your healthcare provider to assess your organs directly. They’ll perform a biopsy to examine any suspicious tissue for signs of cancer.
Cancer staging can provide information on the size of a tumor, where it’s located and whether it’s spread (metastasized). Tests and procedures to stage small intestine cancer usually happen during diagnosis.
The type of small intestine cancer you have (carcinoid tumor, adenocarcinoma, sarcoma or lymphoma) will determine the staging system your healthcare provider uses.
The treatment you receive depends on the type of cancer you have, its stage, where the tumor is located and even the characteristics of the cells inside the tumor. Your preferences will also guide treatment decisions.
Surgery is the most common treatment for small intestine cancer. Surgery may include:
Chemotherapy uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Depending on the chemotherapy treatment, the drugs may target cancer cells in a specific part of your body (regional chemotherapy) or destroy cancer cells throughout your body (systemic chemotherapy).
Your healthcare provider may prescribe chemotherapy after surgery to kill any remaining cancer cells (adjuvant therapy). You may receive systemic chemotherapy if your cancer has metastasized.
Radiation therapy uses high-energy X-rays or other types of radiation to kill cancer cells or keep them from growing. Your healthcare provider may recommend radiation if your cancer can’t be removed surgically. Radiation therapy may also be a part of palliative care to help with symptom relief. Sometimes, radiation is administered alongside chemotherapy (chemoradiation therapy) after surgery to kill any remaining cancer cells.
Your healthcare provider may recommend somatostatin analogs to treat carcinoid tumors of the small intestine. These medications stop your body from making too many hormones. In turn, they can ease symptoms and help control disease. Examples of somatostatin analogs include lanreotide and octreotide.
More research is needed to understand the benefits of using radiation with chemotherapy following surgery for small intestine cancer.
Targeted therapies identify weaknesses in cancer cells and use these weaknesses to destroy them. Researchers are currently studying targeted therapy treatments that may aid in treating adenocarcinomas, GIST and lymphomas.
Immunotherapy boosts your immune system so it’s better able to fight cancer cells. Your immune system naturally fights abnormal cells and dangerous bodily invaders like germs. Unfortunately, cancer cells can sometimes get past your immune system’s defenses. Immunotherapy makes it easier for your immune system to recognize cancer cells and destroy them.
Depending on the type of gene mutations in your tumor, your healthcare provider may recommend immunotherapy.
Clinical trials are studies used to determine if new cancer treatments are safe and effective or better than standard treatments. Currently, treatments involving adjuvant chemotherapy, targeted therapy and immunotherapy, and others are being researched in clinical trials. Ask your healthcare provider if you’re a strong candidate for a clinical trial.
The survival rate varies depending on the type of small intestine cancer, the stage and where the tumor started in your small intestine. For instance, 65% of people diagnosed with early-stage adenocarcinomas are alive five years later. The survival rate in later stages is much less at 4%. Early-stage carcinoid tumors have a five-year survival rate of 95%, while later-stage cancers have a survival rate of 42%.
Ask your healthcare provider about how the characteristics of your cancer will affect your prognosis.
A note from Cleveland Clinic
Understanding likely outcomes and treatment options for small intestine cancer can be challenging because this type of cancer is so rare. Multiple factors will inform your care plan and the likelihood of treatment success. Come to your appointments prepared to speak with your healthcare provider about how the type of tumor you have will shape your treatment options. Depending on your cancer, your healthcare provider may recommend a combination of surgical procedures and therapies to rid of your tumor and prevent your cancer from spreading.
Last reviewed by a Cleveland Clinic medical professional on 05/09/2022.
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