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This PDQ cancer information summary has current information about the causes and treatment of gastrointestinal complications, including constipation, impaction, bowel obstruction, diarrhea, and radiation enteritis. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.
Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Date Last Modified") is the date of the most recent change. The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Supportive and Palliative Care Editorial Board.
CONTENTS
- General Information
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The gastrointestinal (GI) tract is part of the digestive system, which processes nutrients in foods that are eaten and helps pass waste material out of the body. The GI tract includes the stomach and intestines (bowels).
The esophagus and stomach are part of the upper gastrointestinal (digestive) system. 
Anatomy of the lower gastrointestinal (digestive) system showing the colon, rectum, and anus. Other organs that make up the digestive system are also shown. GI complications refer to a range of problems that can affect the digestive system. GI complications are common in people with cancer and may be caused by the cancer itself, or it can be an effect of cancer treatment or the medicines used to manage symptoms.
Children and adults with cancer may experience similar types of GI complications, but the causes and treatment approaches differ based on age and other factors. This page describes the following GI complications in adults, their causes, and treatments:
- Constipation
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Constipation is a condition in which bowel movements are difficult or painful to pass and don't happen very often.
Constipation is caused by the slow movement of stool through the large intestine. As the stool slowly moves through the large intestine, it loses fluid and becomes harder.
A person with constipation may be unable to have a bowel movement, have to push harder to have a bowel movement, or have infrequent bowel movements.
There is no "normal" number of bowel movements for a person with cancer. Each person is different. However, if you have infrequent bowel movements, you may be constipated.
Constipation is a common problem for people with cancer.
Common causes of constipation include older age, changes in diet and fluid intake, and not getting enough exercise. In addition to these common causes of constipation, other causes in people with cancer include:
Assessment of constipation includes a health history, physical exam, and other tests.
The following tests and procedures may be done to help diagnose constipation:
If the cause of the constipation isn't clear from the health history and physical exam, your doctor may order more tests to find out if another problem is causing the constipation:
It is important to prevent and treat constipation to avoid serious problems.
The health care team will talk to you about ways to prevent and treat constipation. Constipation can be uncomfortable and cause distress. If left untreated, constipation may lead to fecal impaction. This is a serious condition in which stool will not pass out of the colon or rectum. It's important to treat constipation to prevent fecal impaction.
Prevention and treatment of constipation are not the same for every person. Keep track of how often you have a bowel movement and do the following to prevent and treat constipation:
People at risk of bleeding or infection should talk with their doctor before using suppositories or enemas.
- Fecal Impaction
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Fecal impaction is a severe form of constipation in which dry, hard stool cannot pass out of the colon or rectum.
Fecal impaction is dry stool that cannot pass out of the body. Constipation that is not treated can lead to fecal impaction. For this reason, the causes of fecal impaction are the same as those of constipation. To learn more, see the section on causes of constipation.
Fecal impaction and constipation share similar symptoms, but fecal impaction may cause other severe symptoms, such as breathing problems, dizziness, or low blood pressure.
Symptoms of fecal impaction include:
It’s important to talk with your health care provider if you have these symptoms.
Assessment of constipation includes a health history, physical exam, and other tests.
The following tests and procedures may be done to help diagnose fecal impaction:
Fecal impaction is usually treated with an enema.
The main treatment for impaction is to moisten and soften the stool so it can be removed or passed out of the body. This is usually done with an enema. Enemas are given only as prescribed by the doctor to reduce the risk of bleeding or infection for patients with low blood counts and because too many enemas can damage the intestine. Some people may need to have stool manually removed from the rectum after it is softened.
- Bowel Obstruction
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A bowel obstruction is a blockage of the small or large intestine by something other than fecal impaction.
A bowel obstruction (blockage) may be caused by a twist in an intestine, a hernia, inflammation, scar tissue from surgery, or cancer. The obstruction keeps the stool from moving through the small or large intestines. The intestine may be partly or completely blocked and can sometimes be blocked in two places.
A bowel obstruction may cause decreased blood flow to an area of the intestines. Blood flow needs to be corrected or the affected tissue may die.
Cancers in the stomach, colon, and ovary can spread to the abdomen and cause an obstruction. People with these cancers or those who have had surgery or radiation therapy to the abdomen have a higher risk of a bowel obstruction. Bowel obstructions are most common during the advanced stages of cancer.
A bowel obstruction can cause pain.
The following may be symptoms of a bowel obstruction:
It's important to talk with your health care provider if you have these symptoms.
Assessment of a bowel obstruction includes a physical exam and imaging tests.
The following tests and procedures may be done to diagnose a bowel obstruction:
Treatment for acute bowel obstruction may include surgery.
Treatment of a chronic, malignant bowel obstruction may include surgery to improve quality of life.
Chronic, malignant bowel obstructions may worsen over time. People with advanced cancer may have chronic bowel obstructions that cannot be removed with surgery. The intestine may be blocked or narrowed in more than one place or the tumor may be too large to remove completely. Treatments include the following:
- Diarrhea
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Diarrhea is frequent, loose, and watery bowel movements.
Acute diarrhea is three or more loose or watery bowel movements in one day. Acute diarrhea may last more than 4 days but less than 2 weeks. Frequent, watery stools that last for more than 2 months is called chronic diarrhea. Diarrhea can occur at any time during cancer treatment. It can be physically and emotionally stressful for people with cancer.
Cancer treatment is the most common cause of diarrhea in people with cancer.
Causes of diarrhea in people with cancer include the following:
Assessment of diarrhea includes a health history, physical exam, and lab tests.
Diarrhea can cause life-threatening complications in people with cancer. It is important to find out the cause so treatment can begin as soon as possible.
The following tests and procedures may be done to diagnose diarrhea and help plan treatment:
Treatment of diarrhea depends on what is causing it.
Treatment depends on the cause of the diarrhea. The doctor may make changes to your medicines, diet, and/or fluids. Treatment of diarrhea may include the following:
- Radiation Enteritis
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Radiation enteritis is inflammation of the intestine caused by radiation therapy.
The small and large intestine are sensitive to radiation. Radiation therapy given to kill cancer cells in the abdomen and pelvis affects normal cells in the lining of the intestines. Radiation therapy stops the growth of cancer cells and other fast-growing cells. Since normal cells in the lining of the intestines grow quickly, radiation treatment to that area can stop those cells from growing. This makes it hard for tissue to repair itself. As cells die and are not replaced, gastrointestinal problems occur over the next few days and weeks.
Radiation enteritis is a condition in which the lining of the intestine becomes swollen and inflamed during or after radiation therapy to the abdomen, pelvis, or rectum. The larger the dose of radiation, the more damage may be done to normal tissue.
Radiation enteritis may be acute or chronic:
The total dose of radiation and other factors affect the risk of radiation enteritis.
The amount of time the enteritis lasts and how severe it is depend on the following:
About 10% to 20% of people treated with radiation to the abdomen will have chronic problems.
Acute and chronic radiation enteritis have similar symptoms.
People with acute radiation enteritis may have the following symptoms:
Symptoms of acute enteritis usually go away 2 to 3 weeks after treatment ends.
Symptoms of chronic radiation enteritis usually appear 6 to 18 months after radiation therapy ends. It can be hard to diagnose. The doctor will first check to see if the symptoms are being caused by a recurrent tumor in the intestine. The doctor will also need to know the person's full history of radiation treatments.
People with chronic radiation enteritis may have the following signs and symptoms:
It's important to talk with your health care provider if you have these symptoms.
Assessment of radiation enteritis includes a physical exam and health history.
A doctor will do a physical exam and ask questions about the following:
Treatment of acute radiation enteritis includes treating the symptoms.
The symptoms of radiation enteritis usually get better with treatment, but if symptoms get worse, then cancer treatment may have to be stopped for a while.
Treatment of acute radiation enteritis or the symptoms may include:
Treatment of chronic radiation enteritis may include the same treatments for acute radiation enteritis.
Treatment of chronic radiation enteritis may include the following:
- Current Clinical Trials
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
- To Learn More About Gastrointestinal Complications
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For more information from the National Cancer Institute about constipation or diarrhea, see the following:
- About This PDQ Summary
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About PDQ
Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.
PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.
Purpose of This Summary
This PDQ cancer information summary has current information about the causes and treatment of gastrointestinal complications, including constipation, impaction, bowel obstruction, diarrhea, and radiation enteritis. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.
Reviewers and Updates
Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Updated") is the date of the most recent change.
The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Supportive and Palliative Care Editorial Board.
Clinical Trial Information
A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).
Permission to Use This Summary
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The best way to cite this PDQ summary is:
PDQ® Supportive and Palliative Care Editorial Board. PDQ Gastrointestinal Complications. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/about-cancer/treatment/side-effects/constipation/GI-complications-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389438]
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