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:
. Duodenum: The first section of your intestine near your stomach.
. Jejunum: The middle section of your small intestine.
. Ileum: The last and longest section of your small intestine.
Most small intestine cancer forms in either your duodenum or ileum.
The different types of small intestine cancer are classified based on the type of cells where the cancer starts.
. Carcinoid tumors start in your neuroendocrine cells. These cells help your body produce hormones and control the release of digestive juices in your small intestine. A little less than half of small intestine cancer cases involve carcinoid tumors.
. Adenocarcinomas start in your glandular epithelial cells (glands) lining your small intestine. About one-third of small intestine cancer cases are adenocarcinomas.
. Sarcomas start in connective tissues like your cartilage or muscle. The most common type of sarcoma that affects your small intestine is called a gastrointestinal stromal tumor (GIST). Previously, these tumors were called leiomyosarcomas.
. Lymphoma starts in cells called lymphocytes. Lymphocytes are a type of white blood cell found in your lymphatic system. Your lymphatic system is an essential part of your immune system that helps your body fight off abnormal cells or germs that may make you sick.
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:
. Abdominal pain or cramps.
. A lump in your abdomen.
. Nausea, vomiting and diarrhea.
. Unexplained weight loss.
. Jaundice (yellowing of your eyes or skin).
. Bloody stool (may appear red or black in the toilet).
. Flushed skin, especially purplish coloring on your arms and upper body.
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:
. Age: Cancer risk for many types of small intestine tumors increases with age. The average age of diagnosis is 65.
. Gender: Small intestine cancer is slightly more common in people assigned male at birth (AMAB).
. Race: Small intestine cancer is slightly more common among people who are Black. The exception is lymphoma, which is more common among people who are white.
. Inherited genetic conditions: Having a biological parent, sibling or child with certain conditions may increase your risk. These conditions include familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome, hereditary nonpolyposis colorectal cancer (HNPCC) and Lynch syndrome.
. Inflammatory conditions: Diseases involving chronic inflammation affecting your bowels, like Crohn’s disease and celiac disease, may increase your risk.
. Autoimmune disorders or a weakened immune system: Conditions that weaken your immune system, like HIV/AIDS, Crohn’s disease and celiac disease, may increase your risk. Treatments like radiation therapy may weaken your immune system and make you more susceptible to small intestine cancer. Drugs that suppress your immune system following an organ transplant may also increase your risk.
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.
. Blood chemistry studies: A test that measures the amounts of certain substances released into your blood by organs and tissues. An unusual (higher or lower than typical) amount of a substance can be a sign of disease in the organ or tissue that produces it. For instance, your healthcare provider may order a liver function test to check for signs that cancer has spread to your liver.
. Complete blood count (CBC): A test that gives your healthcare provider information about your blood cells. Small intestine tumors may cause bleeding that can reduce your red blood cell count and cause anemia.
. Endoscopy: A procedure that uses a thin, tube-like instrument with a light and lens (endoscope) to look inside parts of your gastrointestinal (GI) tract. With an upper endoscopy, your healthcare provider inserts the endoscope into your mouth and uses it to examine your esophagus, stomach and the first part of your intestine near your stomach (duodenum). A double-balloon enteroscopy uses a special endoscope to see deeper inside of your small intestine. During an endoscopy, your healthcare provider may remove tissue samples (biopsy) that can be examined under a microscope for signs of disease.
. Capsule (pill) endoscopy: A procedure involving swallowing a capsule containing a tiny camera. As the capsule travels through your body, it takes pictures of your GI tract that can be downloaded to a computer for your healthcare provider to view. The name can be a bit confusing, but this procedure doesn’t involve using an endoscope.
. CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside of your body, taken from different angles. A computer linked to an X-ray machine displays the images. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly.
. MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves and a computer to make a series of detailed pictures of areas inside of your body. An MRI and CT scan both provide similar information about how a tumor may be impacting soft tissue. Still, CT scans are used more often to diagnose small intestine cancer.
. Abdominal X-ray: An X-ray of the organs in your abdomen. An X-ray is an energy beam that can travel through your body and onto film, making a picture of areas inside of your body.
. Barium X-ray: A procedure that involves coating your GI tract with a chalky substance called barium. The barium makes it easier to see your GI tract on an X-ray. An upper GI series with a small bowel follow-through takes a series of X-rays as the barium travels through your GI tract (esophagus, stomach and small bowel). A lower GI series (barium enema) involves inserting a liquid with barium into your rectum. The barium coats the lower GI tract as X-rays are taken.
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.
. Laparoscopy: A surgical procedure in which a thin tube similar to a telescope (laparoscope) is inserted into your abdomen through a small incision (cut) or multiple small incisions. The laparoscope allows your healthcare provider to assess your abdominal organs for signs of cancer.
. Laparotomy: A surgical procedure in which an incision (cut) is made into your abdominal wall so your healthcare provider can check your abdominal organs 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:
. Resection: Surgery to remove all or part of an organ that contains cancer. Your healthcare provider may remove segments of your small intestine and nearby organs (if the cancer has spread). Afterward, they may perform an anastomosis (joining the cut ends of the intestine together). Your healthcare provider may remove lymph nodes near your small intestine to test them for signs of cancer spread.
. Bypass: Surgery to allow food in your small intestine to go around (bypass) a tumor blocking your intestine, but which can’t be removed.
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.