Small Intestine Cancer
What is the Small Intestine?
The small intestine, also called the small bowel, is part of the body’s gastrointestinal tract or digestive system. Its many jobs include:
- Finshing the breakdown of food that started in the stomach.
- Absorbing the nutrients (carbohydrates, fats, proteins, vitamins, minerals, and water) in food.
- Moving the extra stuff to the large intestine or colon to pass waste out of the body by the rectum.
The average small intestine is 22 feet long. It folds and loops around many times so that it can fit in the belly. The small intestine is lined with finger-like projections, or villi (Latin for “shaggy hair”) that increase the surface area for absorbing nutrients. The small intestine has 3 parts:
- The duodendum is the first and shortest section of the small intestine. It is about 8 inches long. The stomach passes food into the duodenum through a muscle called the pylorus. The pancreatic and bile ducts attach to the duodenum at the ampulla of Vater. They release digestive juices (enzymes) into the duodenum. Enzymes breakdown nutrients so they can be absorbed. The pancreas also releases bicarbonate into the small intestine to neutralize stomach acid. Iron is absorbed in the duodenum.
- Most nutrients in food are absorbed into the bloodstream in the jejunum.
- The ileum is slightly longer than the jejunum. Vitamin B12 and bile salts are absorbed at the end of the ileum. Water and lipids (fats) are absorbed throughout the small intestine. The appendix is found near the section where the ileum meets the large intestine.
What is small intestinal cancer?
There are 5 main types of small intestinal cancers:
- Carcinoid tumors
- Gastrointestinal stromal tumors (GIST)
The first four make up 60-70% of all cancers of the small intestine. (These are outlined in other handouts.)
Adenocarcinomas are 30-40% of small intestinal cancers.
Most of these cancers are found in the duodenum. They may start as a polyp, like cancers of the large intestine. These are treated like colon cancers.
Duodenal cancers may form at the Ampulla of Vater, very close to the pancreas. These tumors are treated like either a pancreas cancer or a colon cancer. The treatment is decided after a pathologist determines their subtype or tissue they most resemble.
Adenocarcinomas that grow in the jejunum or ileum are treated like colon cancers.
Is this a common cancer?
Cancers of the small intestine are rare. In the year 2013, the American Cancer Society predicts more than 102,000 new cases of colon cancer, more than 40,000 new cases of rectal cancer, and only about 2,900 new cases of adenocarcinoma of the small intestine.
What are the risk factors?
- A high-fat diet
- Crohn’s disease
- Celiac disease (gluten intolerance)
- Alcohol use
Persons with some inherited conditions have a higher risk of developing adenocarcinomas of the small intestine. Those include:
o Familial adenomatous polyposis (FAP)
o Hereditary nonpolyposis colorectal cancer (HNPCC/Lynch Syndrome)
o Peutz-Jeghers syndrome (PJS)
o MUTYH-associated polyposis
o Cystic fibrosis
Small intestinal adenocarcinoma happens slightly more often in men. The average age at diagnosis is 60.
What are the symptoms?
The early symptoms of a small bowel tumor are often hard to notice. They include:
- Pain in the mid-abdomen (belly) – may get worse with eating
- Weight loss
- A lump in the abdomen
- Blood in the stool/black stools
- Fatigue/weakness due to anemia
As the tumor grows it may cause an obstruction or blockage of the small bowel causing severe pain, nausea and vomiting.
What is the prognosis?
The prognosis (chance of recovery) depends upon many factors:
- The type of tumor
- The size of the tumor and how deep it has grown into the lining of the small intestine
- Whether the cancer can be completely taken out by surgery
- Whether the cancer has spread to other parts of the body
- Whether the cancer is a new diagnosis or has come back
How is it diagnosed?
These tests may be used to diagnose cancer of the small intestine. They will also help to figure out the stage, or extent of the cancer. This is important information to have when making a treatment plan.
- History and physical exam – review of your symptoms, health habits, past illnesses and treatments.
- Blood tests – CBC (complete blood count) checks the white blood cells (WBC), platelets, and hemoglobin and hematocrit. Blood chemistries and liver function tests look for signs that the cancer is affecting other organs.
- Barium swallow – X-rays upper gastrointestinal tract taken after you swallow barium. (Barium is a contrast liquid.)
- Endoscopy – a procedure that looks at the upper gastrointestinal tract through a long, lighted tube. While you are sedated, the doctor may take pictures and biopsies.
- CT scan – a series of computerized pictures of the inside of the body taken after oral or IV contrast.
- MRI – magnetic resonance imaging uses a magnet, radio waves and a computer to take pictures of the inside of the body.
- Colonoscopy – may be helpful in finding tumors in the lower part of the small intestine.
- Laparoscopy – a surgery done with a scope that lets the surgeon check the abdominal cavity for signs of cancer.
- Biopsy – Checking tissue under a microscope to learn if it is cancer and where it came from. Biopsies may be done during surgery, during an upper endoscopy (EGD) or colonoscopy, and through the abdominal wall with the help of a CT scan or ultrasound .
Doctors use the TNM Staging System as a way to describe how far the cancer has spread. A pathologist looks at tissue under the microscope to learn:
- The extent of the primary tumor (T)
- Whether the tumor has metastasized (spread) to nearby lymph nodes (N)
- Whether the tumor has spread to distant organs (M)
The TNM categories are grouped together and the stages are defined with Roman numerals:
The cancer has grown through the first few layers of the small intestine wall. It has not spread to the nearby lymph nodes.
Stage II is divided into 2 parts:
- Stage IIA
The cancer has grown through most of the layers of the intestinal wall. It has not spread to the lymph nodes.
- Stage IIB
The cancer has grown through the small intestine wall or into nearby tissues or organs. It has not metastasized or spread to nearby lymph nodes or distant organs.
Stage III is divided into 3 parts:
- Stage IIIA
The cancer has grown through the first few layers of the small intestine wall and has spread to 1-3 regional or close lymph nodes.
- Stage IIIB
The cancer has grown through most of the layers of the small intestine and has spread to 1-3 lymph nodes, or it has grown through the intestinal wall, spread to other parts of the small intestine, and spread to
1-3 lymph nodes.
- Stage IIIC
The cancer has grown through at least one layer of the intestinal wall, may have spread to other parts of the intestine, and has spread to more than 4 lymph nodes
The cancer has spread to other organs such as the liver, lungs, peritoneum (the lining of the abdominal cavity), or ovaries.
How is it treated?
Surgery is the most common treatment for cancers of the small intestine. A surgeon may take out part or all of an organ that has cancer. Lymph nodes in the area are taken out and checked under the microscope to see if the cancer has spread. Sometimes the tumor cannot be taken out, but surgery may be needed to bypass or go around a blockage and allow food to pass.
Radiation therapy is a treatment that uses high energy x-rays or other types of radiation to kill cancer cells, or slow their growth. Radiation treats a very specific area. This is called regional therapy. Chemotherapy and radiation are sometimes used together. This makes the radiation more effective. When used this way, the chemotherapy is called a radiosensitizer.
Chemotherapy uses drugs to kill cancer cells or to stop them from dividing. When chemotherapy medicine is injected intravenously (IV) or taken orally in pill form it enters the blood stream and can reach cancer cells throughout the body. This is called systemic therapy.
You may have the chance to take part in a clinical trial. Clinical trials are controlled research studies done to find out if new cancer treatments are safe and effective, or better than the standard treatments. Clinical trials are voluntary and help find better treatments for cancer.
During your treatments you will need blood tests and scans to see how well the treatment is working. These tests help guide decisions to keep going, stop, or change treatments. This is called restaging.
Blood tests and scans will be done from time to time after you have finished your treatments. They can show if your condition has changed or the cancer has recurred, or come back.
The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Any duplication or distribution of the information contained herein is strictly prohibited.
Last Updated: 09/10/2013
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