Oncology Encyclopedia: Small Intestine Cancer
Oncology Encyclopedia: Small Intestine Cancer
—Crystal Heather Kaczkowski, MSc
Cancer of the small intestine is a rare disease that results when abnormal, malignant cells divide out of control. Cancers in this location consist primarily of adenocarcinoma, lymphoma, sarcoma, and carcinoid tumors.
The small intestine is a long tube inside the abdomen divided into three sections: the duodenum, jejunum, and ileum. The function of the small intestine is to break down food and to remove proteins, carbohydrates, fats, vitamins, and minerals. Obstruction of the small intestine by cancer may impair normal passage and digestion of food and nutrients.
These malignancies most often start in the lining of the small intestine, most frequently occurring in the duodenum and jejunum, the sections closest to the stomach. These tumors may obstruct the bowel, causing digestive problems. Adenocarcinoma is the most common cancer of the small intestine, but only accounts for 2% of all tumors in the gastrointestinal tract and 1% of all deaths related to cancer of the gastrointestinal tract. Carcinomas of the small intestine may appear at multiple sites.
This fairly uncommon cancer is typically a non-Hodgkin's type that starts in the lymph tissue of the small intestine. (The body's immune system is comprised of lymph tissue, which assists in fighting infections.) Malignant lymphoma is not often found as a solitary lesion.
Sarcoma malignancies of the small intestine are usually leiomyosarcoma. They most often occur in the smooth muscle lining of the ileum, the last section of the small intestine. Liposarcoma and angiosarcoma occur more rarely in the small intestine.
Carcinoid tumors are most often found in the ileum. In approximately 50% of cases, they appear in multiples.
Approximately 50% of small intestine cancers are adneocarcinomas; 20% are lymphomas; 20% are carcinoid; and about 10% are sarcomas.
Causes and Symptoms
The causes of this cancer are not known, but factors that contribute to its development include exposure to carcinogens such as chemicals, radiation, and viruses. In addition, smoking and a poor diet may contribute to the incidence of small intestine cancer. The incidence of cancer is higher in obese individuals.
Often cancer of the small intestine does not initially produce any symptoms. Gastrointestinal bleeding is perhaps the most common symptom. A doctor should be consulted if any of these symptoms are present:
involuntary weight loss
a lump in the abdominal region
blood in the stool
pain or cramping in the abdominal region
Evaluation begins by taking a patient's medical history and conducting a physical examination. If a patient experiences symptoms, a doctor may suggest the following tests:
Upper gastrointestinal x ray/upper GI series: To allow the stomach to be seen easier on an x ray, the patient drinks a liquid called barium. This test can be conducted in either a doctor's office or a radiology department at a hospital.
CT scan (computed tomography): A computerized x ray that takes a picture of the abdomen.
MRI scan (magnetic resonance imaging): A imaging technique that uses magnetic waves to take a picture of the abdomen.
Ultrasound: An imaging technique that uses sound waves to locate tumors.
Endoscopy: An endoscope is a thin, lighted tube which is placed down the throat to reach the first section of the small intestine (duodenum). During this procedure, the doctor may take a biopsy, in which a small piece of tissue is removed for examination of cancereous cells under a microscope.
If small intestine cancer is evident, more tests will be conducted to determine if cancer has spread to other parts of the body.
Cancer treatment often requires a team of specialists and may include a surgeon, medical oncologist, radiation oncologist, nurse, physical therapist, occupational therapist, dietitian, and or a social worker.
Clinical Staging, Treatments, and Prognosis
As with many other types of cancer, malignancies of the small intestine can be classified as localized, regional spread, or distant spread.
Localized: The cancer has not spread beyond the wall of the organ it developed in.
Regional spread: The cancer has spread from the organ it started in to other tissues such as muscle, fat, ligaments, or lymph nodes.
Distant spread: The cancer has spread to tissues or organs outside of where it originated such as the liver, bones, or lungs.
Treatment options for small intestine cancer most often include surgery, and possibly radiation therapy, chemotherapy, and/or biological therapy. Cancer of the small intestine is treatable and sometimes curable depending on the histology. Removing the cancer through surgery is the most common treatment. If the tumor is large, a small portion may be removed if resection of the small intestine is possible. For larger tumors, surgery requires removing a greater amount of the surrounding normal intestinal tissue, in addition to some surrounding blood vessels and lymph nodes.
Radiation therapy kills cancer cells and reduces the size of tumors through the use of high-energy x rays. Radiation therapy may come from an external source using a machine or an internal source. Internal-based therapy involves the use of radioisotopes to administer radiation through thin plastic tubes to the area of the body where cancer cells are found. Side effects of radiation therapy include:
loss of appetite
nausea and vomiting
mild temporary, sunburn-like skin changes
difficulty tolerating milk products
Chemotherapy kills cancer cells with drugs taken orally or by injection in a vein or muscle. It is referred to as a systemic treatment due to fact that it travels through the bloodstream and kills cancer cells outside the small intestine. Adjuvant chemotherapy may be given following surgery to ensure all cancer cells are killed. Some side effects of chemotherapy are:
nausea and vomiting
loss of appetite (anorexia)
temporary hair loss (alopecia)
fatigue, as a result of a low red blood cell count
higher likelihood of infection or bleeding due to low white blood cell counts and low blood platelets, respectively
Radiation and chemotherapy are seldom beneficial in small intestinal cancers.
Utilizing the body's immune system, biological therapy stimulates the body to combat cancer. Natural materials from the body or other laboratory-produced agents are designed to boost, guide, or restore the body's ability to fight disease.
Treatment options for small interstine cancers are based on the type of cells found—adenocarcinoma, lymphoma, sarcoma, or carcinoid tumor—rather than the clinical staging system.
Treatment of adenocarcinoma of the small intestine may consist of:
surgical removal of the tumor
If the cancer cannot be removed by resection of the small intestine, surgery may be performed to bypass the cancer to allow food to travel through the intestine.
symptom relief with radiation therapy
chemotherapy or biological therapy in a clinical trial setting
a clinical trial involving radiation and drug therapy (with or without chemotherapy) to elicit greater sensitivity to radiation using radiosensitizers
Treatment of lymphoma of the small intestine may consist of:
surgical removal of the cancer and lymph nodes in close proximity to it
Surgery accompanied by radiation therapy or adjuvant chemotherapy. If the disease is localized to the bowel wall, then surgical resection alone or combined chemotherapy should be considered. If the disease has extended to the regional lymph nodes, then surgical resection and combination chemotherapy is suggested at the time of diagnosis.
For extensive lymphoma or lymphoma that cannot be removed surgically, chemotherapy with or without additional radiation therapy is frequently used to reduce the risk of recurrence.
Treatment of leiomyosarcoma of the small intestine may consist of:
surgical removal of the cancer
When cancer cannot be removed by resection, surgical bypass of the tumor is recommended to allow food to pass.
For unresectable metastatic disease, surgery, radiation therapy, or chemotherapy is suggested in order to alleviate symptoms.
For unresectable primary or metastatic disease, a clinical trial evaluating the benefits of new anticancer drugs (chemotherapy) and biological therapy.
For recurrent small intestine cancer, treatment may consist of the following measures, if the cancer has returned to one area of the body only:
surgical removal of the cancer
symptom relief using chemotherapy or radiation therapy
a clinical trial using radiation and drug therapy (with or without chemotherapy) to elicit greater sensitivity to radiation using radiosensitizers
For recurrent metastatic adenocarcinoma or leiomyosarcoma, there is no standard effective chemotherapy treatment. Patients should be regarded as candidates for clinical studies assessing new anticancer drugs or biological agents.
For carcinoid tumors at least than 1 cm in size, surgical removal of the tumor and surrounding tissue is possible. Carcinoid tumors often grow and spread slowly, therefore, approximately half are found at an early or localized stage. By the time of sugery, 80% of the tumors over 2 cm in diameter have metastasized locally or to the liver.
The prognosis or likelihood of recovery depends on the type of cancer, the overall health of the patient, and whether the cancer has spread to other regions or is only localized in the small intestine. A cure depends on the ability to remove the cancer completely with surgery. Adenocarcinoma is most common in the duodenum, however, patient survival is less likely for individuals with cancer is in this area compared with those patients with tumors in the jejunum or ileum due to reduced rates of surgery to remove cancer. Between 1985-1995, there were 4,995 cases of adenocarcinoma of the small intestine reported to the National Cancer Database. Of these malignancies, 55% occurred in the duodenum, 13% in the ileum, 18% in the jejunum, and 14% were in unspecified areas. The National Cancer Database reported a median survival of 19.7 months for these patients with an overall 5-year disease survival rate of 30.5%. For resectable adenocarcinoma, the National Cancer Institute reports an overall five-year survival rate of only 20%, whereas resectable leiomyosarcoma's survival rate is reported at approximately 50%. One study found the overall rate of metastatic spread of leiomyosarcoma ranged from 24–50%; this cancer most often spread to the liver. Five-year survival in 705 patients with leiomyosarcoma was reported at 28%. Surgery is the preferred treatment for smooth muscle tumors. Little benefit was found for irradiation or chemotherapy, or for these therapies combined. Patients over 75 years of age have a significantly poorer survival rate than younger people. In addition, patients with poorly differentiated tumors have a poorer prognosis than those with moderately or well-differentiated tumors. Survival rate decreases with progression of disease by stage: localized 47.6%; regional 31%; distant 5.2%.
Alternative and Complementary Therapies
Bovine and shark cartilage is currently being explored in clinical trials for antitumor properties, but as of mid-2001 there is not enough evidence to warrant its use. Some popular herbs that are purported to have therapeutic effects in cancer treatment include echinacea, garlic, ginseng, and ginger. Laboratory studies have shown that echinacea has the potential to control the growth of cancerous cells, but more studies are needed to confirm efficacy in humans. In addition, dosage and toxicity levels still need to be established. Some studies suggest that diets high in garlic reduce the risk of stomach, esophageal, and colon cancers. There is still debate regarding the best form of garlic to take—whole raw garlic or garlic in tablet form; aged or fresh garlic; garlic with odor or "deodorized" garlic. Ginger is often recommended for its beneficial effects on the digestive system, but evidence has not confirmed efficacy in cancer treatment. Ginseng in excessive amounts can be very toxic, causing vomiting, bleeding, and death. Patients should not take herbal remedies without consulting their physicians, particularly if they intend to combine the herbs with prescription drugs. Herb and drug combinations can sometimes result in toxic interactions.
Coping With Cancer Treatment
Pain is a common problem for people with some types of cancer, especially when the cancer grows and presses against other organs and nerves. Pain may also be a side effect of treatment. However, pain can generally be relieved or reduced with prescription medicines or over-the-counter drugs as recommended by the doctor. Other ways to reduce pain, such as relaxation exercises, may also be useful. It is important for patients to report pain to their doctors, so that steps can be taken to help relieve it.
Depression may affect approximately 15–25% of cancer patients, particularly if the prognosis for recovery is poor. A number of antidepressant medications are available from physicians to alleviate feelings of depression. Counseling with a psychologist or psychiatrist also may help patients deal with depression.
As of 2001, Glivec (STI-571, or imatinib mesylate) is in clinical trials for treatment of gastrointestinal stromal tumors, as well as for leukemia and glioblastoma, a type of brain tumor. An open trial (GIST trial SWOGS0033) led by Southwest Oncology Group will test those individuals with metastatic or recurrent disease using two doses of the drug.
Clinical trials may be suitable for patients suffering from small intestine cancer. The principal investigator should be contacted regarding participation in appropriate trials. For information about cancer trials, patients can visit the National Cancer Institute web site at .
Most people who develop cancer do not have inherited genetic abnormalities. Their genes have been damaged after birth by substances in their environment. A substance that damages deoxyribonucleic acid (DNA) in a way that can lead to cancer is called a carcinogen. Carcinogens include certain chemicals, certain types of radiation, and viruses. Asbestos is one substance that is suspected of contributing to the development of small intestinal cancer. Although the precise causes of cancer are not known, a variety of factors are known to contribute to the development of cancer including tobacco smoke, and poor dietary habits such as high-fat diet. Eating a diet rich in fruits and vegetables and low in fat may reduce the likelihood of cancer. Studies have demonstrated that individuals who were protected from cancer ate a greater variety of foods and nutrients compared to those with cancer. Several fruits, vitamins, and minerals were found particularly protective against intestinal cancer including vitamin B6, folate, niacin, and iron. Some studies have linked eating large amounts of salt-cured, salt-pickled, and smoked foods to cancers of the digestive system. Other studies have linked stomach cancers, specifically intestinal cancer, to a lack of fruits, vegetables, and fiber in the diet. For prevention of cancer, it is important to avoid carcinogens (smoking, chemicals) and known risk factors, and to pursue a healthy lifestyle which includes moderate alcohol intake, regular exercise, a low-fat diet, and a diet rich in fruits and vegetables. Modifying genetic predispositions through risk factor reduction can also assist in prevention.
Due to the side effects of radiation and chemotherapy, individuals must make a deliberate effort to eat as nutritiously as possible. Those who experience pain, nausea, or diarrhea may want to discuss treatments options with their doctor to ease these side effects.
Eating well during cancer treatment means getting enough calories and protein to help prevent weight loss
Questions to Ask the Doctor
What is my diagnosis?
Is there any evidence the cancer has spread?
What is the stage of the disease?
What are my treatment choices?
What new treatments are being studied?
Would a clinical trial be appropriate for me?
What are the expected benefits of each kind of treatment?
What are the risks and possible side effects of each treatment?
How often will I have treatments?
How long will treatment last?
Will I have to change my normal activities?
What is the treatment likely to cost?
Is infertility a side effect of cancer treatment? Can anything be done about it?
What is my prognosis?
and maintain strength. Eating nutritiously may also help an individual feel better.
Kelsen, David, Bernard Levin, and Joel Tepper. Principles and Practice of Gastrointestinal Oncology. Philadelphia: Lippincott Williams & Wilkins Publishers, 2001.
Howe, J.R., et al. "The American College of Surgeons Commission on Cancer and the American Cancer Society. Adenocarcinoma of the Small Bowel: Review of the National Cancer Data Base, 1985-1995." Cancer 86 (1999): 2693-2706.
The National Cancer Institute (NCI). For information contact the Public Inquiries Office: Building 31, Room 10A31, 31 Center Drive, MSC 2580, Betheseda, MD 20892-2580 USA. (301) 435-3848 or 1-800-4-CANCER. or or .
National Center for Complementary and Alternative Medicine (NCCAM). 31 Center Dr., Room #5B-58, Bethesda, MD 20892-2182. (800) NIH-NCAM. Fax: (301) 495-4957. .
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