Cancer and Gastrointestinal Complications

by National Cancer Institute

This patient summary on gastrointestinal complications is adapted from a summary written for health professionals by cancer experts. This and other credible information about cancer treatment, screening, prevention, supportive care, and ongoing clinical trials, is available from the National Cancer Institute. Gastrointestinal complications such as constipation, impaction, bowel obstruction, diarrhea, and radiation enteritis are common problems for cancer patients, with causes that include the cancer itself or treatment of the cancer. This brief summary describes the differences between constipation, impaction, bowel obstruction, and diarrhea; their causes; and their treatment. Treatment of children is different from adults. The doctor will prescribe treatments according to the child's age and diagnosis.

Constipation is the slow movement of feces (stool or body wastes) through the large intestine resulting in infrequent bowel movements and the passage of dry, hard stools. The longer it takes for the stool to move through the large intestine, the more fluid is absorbed and the drier and harder the stool becomes.

Inactivity, immobility, or physical and social barriers (for example, bathrooms being unavailable or inconveniently located) can make constipation worse. Depression and anxiety caused by cancer treatment or cancer pain can also lead to constipation. The most common causes of constipation are not drinking enough fluids and taking pain medications.

Constipation is annoying and uncomfortable, but fecal impaction (a collection of dry, hard stool in the colon or rectum) can be life-threatening. Patients with a fecal impaction may not have gastrointestinal symptoms. Instead, they may have circulation, heart, or breathing problems. If fecal impaction is not recognized, the signs and symptoms will get worse and the patient could die.

A bowel obstruction is a partial or complete blockage of the small or large intestine by a process other than fecal impaction. Bowel obstructions are classified by the type of obstruction, how the obstruction occurred, and where it is. Tumors growing inside or outside the bowel, and scar tissue that develops after surgery, can affect bowel function and cause a partial or complete obstruction. Patients who have colostomies are especially at risk of developing constipation, which can lead to bowel obstruction.

Diarrhea can occur at any time during cancer treatment. Although diarrhea occurs less often than constipation, it can be physically and emotionally devastating for patients who have cancer. Diarrhea can cause:

• Changes in eating patterns.
• A loss of body fluids.
• Chemical imbalances in the blood.
• Impairments in physical function.
• Excessive tiredness.
• Skin problems.
• A decrease in physical activity.
• Problems that can be life-threatening in some patients.

Diarrhea is an abnormal increase in the amount of fluid in the stool that lasts more than 4 days but less than 2 weeks. It may also be described as an abnormal increase in the amount of fluid in the stool and the passage of more than 3 unformed stools during a 24-hour period. Diarrhea is considered a long-term problem when it lasts longer than 2 months.

Radiation enteritis is a condition in which the lining of the bowel becomes swollen and inflamed during or after radiation therapy to the abdomen, pelvis, or rectum. The large and small bowels are very sensitive to radiation. The larger the dose of radiation, the greater the damage to normal bowel tissue. Most tumors in the abdomen and pelvis need large doses, and almost all patients receiving radiation to the abdomen, pelvis, or rectum will show signs of acute enteritis.

Acute symptoms are those that appear during the first course of radiation therapy and up to 8 weeks later. Chronic radiation enteritis may appear months to years after radiation therapy is completed, or it may begin as acute enteritis and continue after treatment stops. Only 5% to 15% of persons treated with radiation to the abdomen will develop chronic problems. Several factors affect how long the enteritis will last and how severe it will be:

• The dose of radiation given.
• The tumor size and how much it has spread.
• The amount of normal bowel treated.
• Whether chemotherapy was given at the same time as the radiation therapy.
• Whether radiation implants were used.
• Whether the patient has high blood pressure, diabetes, pelvic inflammatory disease, or poor nutrition, or has had surgery to the abdomen or pelvis. These conditions can decrease blood flow to the bowel wall and affect bowel movement, increasing the chance of radiation injury.

Constipation

Description and Causes

Common factors that may cause constipation in healthy people are eating a low-fiber diet, postponing visits to the toilet, using laxatives and enemas excessively, not drinking enough fluids, and exercising too little. In persons with cancer, constipation may be a symptom of cancer, a result of a growing tumor, or a result of cancer treatment. Constipation may also be a side effect of medications for cancer or cancer pain and may be a result of other changes in the body (organ failure, decreased ability to move, and depression). Other causes of constipation include dehydration and not eating enough. Cancer, cancer treatment, aging, and declining health can contribute to causing constipation.

More specific causes of constipation that can result in bowel impaction include:

Diet

• Not including enough high-fiber foods in the diet.
• Not drinking enough water or other fluids.

Changed Bowel Habits

• Repeatedly ignoring the urge to pass stool.
• Using too many laxatives and enemas.

Immobility and Lack of Exercise

• Spinal cord injury, spinal cord compression, bone fractures, fatigue, weakness, long periods of bedrest.
• Inability to tolerate movement and exercise due to respiratory or cardiac problems.

Medications

• Chemotherapy treatments.
• Pain medications.
• Medications for anxiety and depression.
• Stomach antacids.
• Diuretics.
• Vitamin supplements such as iron and calcium.
• Sleep medications.
• General anesthesia.

Bowel Disorders

• Irritable colon.
• Diverticulitis.
• Tumor.

Muscle and Nerve Disorders (nerve damage can lead to loss of muscle tone in the bowel)

• Brain tumors.
• Spinal cord compression from a tumor or other spinal cord injury.
• Stroke or other disorders that cause muscle weakness or movement.
• Weakness of the diaphragm or abdominal muscles making it difficult to take a deep breath and push to have a bowel movement.

Body Metabolism Disorders

• Under-secretion of the thyroid gland.
• Increased level of calcium in the blood.
• Low levels of potassium or sodium in the blood.
• Diabetes with nerve dysfunction.

Environmental Factors

• Needing assistance to go to the bathroom.
• Being in unfamiliar surroundings or a hurried atmosphere.
• Living in extreme heat leading to dehydration.
• Needing to use a bedpan or bedside commode.
• Lack of privacy.

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