Gastrointestinal Complications (PDQ®)
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.
This summary is about gastrointestinal complications in adults with cancer.
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.
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 include:
- Chemotherapy treatments.
- Pain medications, including opioids.
- Medications for anxiety and depression.
- Stomach antacids.
- Vitamin supplements such as iron and calcium.
- Sleep medications.
- General anesthesia.
- Not drinking enough water or other fluids.
- Repeatedly ignoring the urge to pass stool.
- Using too many laxatives and enemas.
- 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.
- 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.
- 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.
- 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.
Assessment of Constipation
A medical history and physical examination can identify the causes of constipation. The examination may include a digital rectal exam (the doctor inserts a gloved, lubricated finger into the rectum to check for stool impaction) or a test for blood in the stool. If cancer is suspected, a thorough examination of the rectum and colon may be done with a lighted tube inserted through the anus and into the colon. The following questions may be asked:
- What is your normal bowel pattern? How often do you have a bowel movement? When and how much?
- When was your last bowel movement? What was it like (how much, hard or soft, color)? Was there any blood?
- Has your stomach hurt or have you had any cramping, nausea, vomiting, pain, gas, or feeling of fullness near the rectum?
- Do you use laxatives or enemas regularly? What do you normally do to relieve constipation? Does this usually work?
- What kind of food do you eat? How much and what type of fluids do you drink daily?
- What medicine are you taking? How much and how often?
- Is this constipation a recent change in your normal habits?
- How many times a day do you pass gas?
Treatment of constipation includes prevention (if possible), elimination of possible causes, and limited use of laxatives. Constipation caused by opioid pain medicine may be treated with a drug given by injection. Suggestions for the patient's treatment plan may include the following:
- Keep a record of all bowel movements.
- Increase the fluid intake by drinking eight 8-ounce glasses of fluid each day (patients who have kidney or heart disease may need to limit fluid intake).
- Exercise regularly, including abdominal exercises in bed or moving from the bed to chair if the patient cannot walk.
- Increase the amount of dietary fiber by eating more fruits (raisins, prunes, peaches, and apples), vegetables (squash, broccoli, carrots, and celery), 100% whole grain cereals and breads, and bran. Patients must drink more fluids when increasing dietary fiber or they may become constipated. (See the PDQ summary on Nutrition in Cancer Care for more information.) Patients who have had a bowel obstruction or have undergone bowel surgery (for example, a colostomy) should not eat a high-fiber diet.
- Drink a warm or hot drink about one half-hour before the patient's usual time for a bowel movement.
- Provide privacy and quiet time when the patient needs to have a bowel movement.
- Help the patient to the toilet or provide a bedside commode instead of a bedpan.
- Take only medications prescribed by the doctor.
- Do not use suppositories or enemas unless ordered by the doctor. In some cancer patients, these treatments may lead to bleeding, infection, or other harmful side effects.
Description and Causes
Five major factors can cause impaction:
- Opioid pain medications.
- Inactivity over a long period.
- Changes in diet.
- Mental illness.
- Long-term use of laxatives.Regular use of laxatives for constipation contributes most to the development of constipation and impaction. Repeated use of laxatives in higher and higher doses makes the colon less able to signal the need to have a bowel movement. (See the Constipation section for causes of constipation that can result in impaction.)
Patients with impaction may have symptoms similar to patients with constipation, or they may have back pain (the impaction presses on sacral nerves) or bladder problems (the impaction presses on the ureters, bladder, or urethra). The patient's abdomen may become enlarged causing difficulty breathing, rapid heartbeat, dizziness, and low blood pressure. Other symptoms can include explosive diarrhea (as stool moves around the impaction), leaking stool when coughing, nausea, vomiting, abdominal pain, and dehydration. Patients who have an impaction may become very confused and disoriented with rapid heartbeat, sweating, fever, and high or low blood pressure.
Assessment of Impaction
The doctor will ask questions similar to those in the Assessment of Constipation section and do a physical examination to find out if the patient has an impaction. The examination may also include x-rays of the abdomen and/or chest, blood tests, and an electrocardiogram (a test that shows the activity of the heart).
Treatment of Impaction
Impactions are usually treated by moistening and softening the stool with an enema. Enemas must be given very carefully as prescribed by the doctor since too many enemas can damage the bowel. Some patients may need to have stool manually removed from the rectum after it is softened. Glycerin suppositories may also be prescribed. Laxatives that stimulate the bowel and cause cramping must be avoided since they can damage the bowel even more.
Description and Causes
A bowel obstruction may be caused by a narrowing of the intestine from inflammation or damage to the bowel, tumors, scar tissue, hernias, twisting of the bowel, or pressure on the bowel from outside the intestinal tract. It can also be caused by factors that interfere with the function of muscles, nerves, and blood flow to the bowel. Most bowel obstructions occur in the small intestine and are usually caused by scar tissue or hernias. The rest occur in the colon (large intestine) and are usually caused by tumors, twisting of the bowel, or diverticulitis. Symptoms will vary depending on whether the small or large intestine is involved.
The most common cancers that cause bowel obstructions are cancers of the colon, stomach, and ovary. Other cancers, such as lung and breast cancers and melanoma, can spread to the abdomen and cause bowel obstruction. Patients who have had abdominal surgery or radiation are at a higher risk of developing a bowel obstruction. Bowel obstructions are most common during the advanced stages of cancer.
Assessment of Bowel Obstruction
The doctor will do a physical examination to find out whether the patient has abdominal pain, vomiting, or any movement of gas or stool in the bowel. Blood and urine tests may be done to detect any fluid and blood chemistry imbalances or infection. Abdominal x-rays and a barium enema may also be done to find the location of the bowel obstruction.
Treatment of Acute Bowel Obstruction
Patients who have abdominal symptoms that continue to become worse must be monitored frequently to prevent or detect early signs and symptoms of shock and constricting obstruction of the bowel. Medical treatment is necessary to prevent fluid and blood chemistry imbalances and shock.
A nasogastric tube may be inserted through the nose and esophagus into the stomach, or a colorectal tube may be inserted through the rectum into the colon to relieve pressure from a partial bowel obstruction. The nasogastric tube or colorectal tube may decrease swelling, remove fluid and gas build-up, or decrease the need for multiple surgical procedures; however, surgery may be necessary if the obstruction completely obstructs the bowel.
Treatment of Chronic, Malignant Bowel Obstruction
Patients who have advanced cancer may have chronic, worsening bowel obstruction that cannot be removed with surgery. Sometimes, the doctor may be able to insert an expandable metal tube called a stent into the bowel to open the area that is blocked.
When neither surgery nor a stent placement is possible, the doctor may insert a gastrostomy tube through the wall of the abdomen directly into the stomach by a very simple procedure. The gastrostomy tube can relieve fluid and air build-up in the stomach and allow medications and liquids to be given directly into the stomach by pouring them down the tube. A drainage bag with a valve may also be attached to the gastrostomy tube. When the valve is open, the patient may be able to eat or drink by mouth without any discomfort because the food drains directly into the bag. This gives the patient the experience of tasting the food and keeping the mouth moist. Solid food should be avoided because it may block the tubing to the drainage bag.
If the patient's comfort is not improved with a stent or gastrostomy tube, and the patient cannot take anything by mouth, the doctor may prescribe injections or infusions of medications for pain and/or nausea and vomiting.
In cancer patients, the most common cause of diarrhea is cancer treatment (chemotherapy, radiation therapy, bone marrow transplantation, or surgery). Other causes of diarrhea include antibiotic therapy, stress and anxiety related to being diagnosed with cancer and undergoing cancer treatment; and infection. Infection may be caused by viruses, bacteria, fungi, or other harmful microorganisms. Antibiotic therapy can cause inflammation of the lining of the bowel, resulting in diarrhea that often does not respond to treatment. Other causes of diarrhea in cancer patients include:
- The cancer itself.
- Physical reactions to diet.
- Medical problems and diseases other than cancer.
- The laxative regimen.
- Bowel impaction with leakage of stool around the blockage.
Undergoing surgery to the stomach and/or intestines can affect normal bowel function and cause diarrhea. Some chemotherapy drugs cause diarrhea by affecting how nutrients are broken down and absorbed in the small bowel. Radiation therapy to the abdomen and pelvis can cause inflammation of the bowel. Patients may have problems digesting food, and experience gas, bloating, cramping, and diarrhea. These symptoms may last up to 8 to 12 weeks after therapy or may not develop for months or years. Treatment may include diet changes, medications, or surgery. Patients who are undergoing radiation therapy while receiving chemotherapy often experience severe diarrhea. Hospitalization may not be required, since an outpatient clinic or special home care nursing may give the care and support needed. Each patient's symptoms should be evaluated to determine if intravenous fluids or special medication should be prescribed.
Patients who undergo donor bone marrow transplantation may develop graft-versus-host disease (GVHD). Stomach and intestinal symptoms of GVHD include nausea and vomiting, severe abdominal pain and cramping, and watery, green diarrhea. Symptoms may occur 1 week to 3 months after transplantation. Some patients may require long-term treatment and diet management.
Because diarrhea can be life-threatening, it is important to identify the cause so treatment can begin as soon as possible. The doctor may ask the following questions:
- How often have you had bowel movements in the past 24 hours?
- When was your last bowel movement? What was it like (how much, how hard or soft, what color)? Was there any blood?
- Have you been dizzy, extremely drowsy, or had any cramping, abdominal pain, nausea, vomiting, fever, or rectal bleeding?
- What have you eaten? What and how much have you had to drink in the past 24 hours?
- Have you lost weight recently? How much?
- How often have you urinated in the past 24 hours?
- What medicine are you taking? How much and how often?
- Have you traveled recently?
The doctor will also do a physical examination that should include checking blood pressure, pulse, and respirations; evaluation of the skin and tissue lining the inside of the mouth to check for blood circulation and amount of fluid in the tissue; examination of the abdomen for pain, tenderness, and bowel sounds; and a rectal exam to check for stool impaction and collect stool to test for blood.
In some cases, abdominal x-rays may also be done to identify bowel obstruction or other abnormalities. In rare cases, a thorough examination of the rectum and colon may be done with a lighted tube inserted through the anus and into the colon.
Diarrhea is treated by identifying and treating the problems causing diarrhea. For example, diarrhea may be caused by stool impaction and medications to prevent constipation. The doctor may make changes in medications, diet, and fluids. Diet changes that may help decrease diarrhea include eating small frequent meals and avoiding some of the following foods:
- Milk and dairy products.
- Spicy foods.
- Caffeine-containing foods and drinks.
- Some fruit juices.
- Gas-forming foods and drinks.
- High-fiber foods.
- High-fat foods.
For mild diarrhea, a diet of bananas, rice, apples, and toast (the BRAT diet) may decrease the frequency of stools. Patients should be encouraged to drink up to 3 quarts of clear fluids per day including water, sports drinks, broth, weak decaffeinated tea, caffeine-free soft drinks, clear juices, and gelatin. For severe diarrhea, the patient may need intravenous fluids or other forms of intravenous nutrition. (See the Diarrhea section in the PDQ summary on Nutrition in Cancer Care for more information.)
To manage diarrhea caused by graft-versus-host disease (GVHD), the doctor may recommend a special 5-phase diet. During phase 1, the patient receives intravenous fluids and nothing by mouth to rest the bowel until the diarrhea slows down. In phase 2, the patient may begin drinking fluids. If the patient is able to drink fluids and the diarrhea improves, he or she may begin phase 3, eating solid foods that are low-fiber, low-fat, low-acid, and do not irritate the stomach. In phase 4, the patient is gradually allowed to eat regular foods. If the patient is able to eat regular foods without any episodes of diarrhea, he or she may begin phase 5, eating their regular diet. Many patients may continue to have problems digesting milk and dairy products.
Depending on the cause of the diarrhea, the doctor may change the laxative therapy regimen or may prescribe medications that slow down bowel activity, decrease bowel fluid secretions, and allow nutrients to be absorbed by the bowel.
Probiotics are live microorganisms taken as nutritional supplements or added to foods to improve digestion and bowel function. There are many types of probiotics, such as Lactobacillus. Probiotics help support the normal balance of bacteria in the colon. They may be used to:
- Prevent diarrhea caused by an infection or by antibiotics.
- Prevent or treat inflammatory bowel disease, irritable bowel syndrome, and gastroenteritis.
In a clinical trial of patients with cancer who received radiation therapy to the pelvis, those who took a probiotic product had less severe and less frequent diarrhea with no side effects, compared to those who took a placebo. Probiotics are being studied in patients with familial adenomatous polyposis and in adults, children, and adolescents who are undergoing stem cell transplantation.
Causes and Symptoms
Radiation therapy stops the growth of rapidly dividing cells, such as cancer cells. Since normal cells in the lining of the bowel also divide rapidly, radiation treatment can stop those cells from growing, making it difficult for bowel tissue to repair itself. As bowel cells die and are not replaced, gastrointestinal problems develop over the next few days and weeks.
- Abdominal cramps.
- Frequent urges to have a bowel movement.
- Rectal pain, bleeding, or mucus-like discharge.
- Watery diarrhea.
Symptoms of acute enteritis usually get better 2 to 3 weeks after treatment ends.
Patients with chronic enteritis may have the following symptoms:
- Wave-like abdominal pain.
- Bloody diarrhea.
- Frequent urges to have a bowel movement.
- Greasy and fatty stools.
- Weight loss.
Less common symptoms of chronic enteritis are bowel obstruction, holes in the bowel, and heavy rectal bleeding.
Symptoms usually appear 6 to 18 months after radiation therapy ends. Before determining that chronic radiation enteritis is causing these symptoms, recurrent tumors need to be ruled out. The radiation history of the patient is important in making the correct diagnosis.
Assessment of Radiation Enteritis
Patients will be given a physical exam and be asked questions about the following:
- Usual pattern of bowel movements.
- Pattern of diarrhea, including when it started; how long it has lasted; frequency, amount, and type of stools; and other symptoms (such as gas, cramping, bloating, urgency, bleeding, and rectal soreness).
- Nutritional health of the patient, including height and weight, usual eating habits, any change in eating habits, amount of fiber in the diet, and signs of dehydration (such as poor skin tone, increased weakness, or feeling very tired).
- Current level of stress, ability to cope, and changes in lifestyle caused by the enteritis.
Treatment of Acute Radiation Enteritis
Treatment of acute enteritis includes treating the diarrhea, loss of fluids, poor absorption, and stomach or rectal pain. These symptoms usually get better with medications, changes in diet, and rest. If symptoms become worse even with this treatment, then cancer treatment may have to be stopped, at least temporarily.
Medications that may be prescribed include antidiarrheals to stop diarrhea, opioids to relieve pain, and steroid foams to relieve rectal inflammation and irritation. If patients with pancreatic cancer have diarrhea during radiation therapy, they may need pancreatic enzyme replacement, because not having enough of these enzymes can cause diarrhea.
Nutrition also plays a role in acute enteritis. Intestines damaged by radiation therapy may not make enough or any of certain enzymes needed for digestion, especially lactase. Lactase is needed for the digestion of milk and milk products. A lactose-free, low-fat, and low-fiber diet may help to control symptoms of acute enteritis.
- Milk and milk products, except buttermilk and yogurt. Processed cheese may not cause problems because the lactose is removed during processing. Lactose-free milkshake supplements, such as Ensure, may also be used.
- Whole-bran bread and cereal.
- Nuts, seeds, and coconut.
- Fried, greasy, or fatty foods.
- Fresh and dried fruit and some fruit juices (such as prune juice).
- Raw vegetables.
- Rich pastries.
- Popcorn, potato chips, and pretzels.
- Strong spices and herbs.
- Chocolate, coffee, tea, and soft drinks with caffeine.
- Alcohol and tobacco.
- Fish, poultry, and meat that are cooked, broiled, or roasted.
- Bananas, applesauce, peeled apples, and apple and grape juices.
- White bread and toast.
- Macaroni and noodles.
- Baked, boiled, or mashed potatoes.
- Cooked vegetables that are mild, such as asparagus tips, green and waxed beans, carrots, spinach, and squash.
- Mild processed cheese, eggs, smooth peanut butter, buttermilk, and yogurt.
- Eat food at room temperature.
- Drink 3 liters (about 12 eight-ounce glasses) of fluid a day.
- Allow carbonated beverages to lose their fizz before drinking them.
- Add nutmeg to food to help decrease movement of the gastrointestinal tract.
- Start a low-fiber diet on the first day of radiation therapy.
Treatment of Chronic Radiation Enteritis
Treatment of the symptoms of chronic radiation enteritis is the same as treatment of acute radiation enteritis. Surgery is used to treat severe damage. Fewer than 2% of affected patients will need surgery to control their symptoms.
Two types of surgery may be used:
- Intestinal bypass, a procedure in which the doctor creates a new pathway for the flow of bowel contents.
- Complete removal of the diseased intestines.
The patient's general health and the amount of damaged tissue are considered before surgery is attempted, however, because wound healing is often slow and long-term tubefeeding may be needed. Even after surgery, many patients still have symptoms.
To lower the risk that chronic radiation enteritis will occur, different treatment methods are used to reduce the area that is exposed to radiation. Patients may be positioned to protect as much of the small bowel as possible from the radiation treatment, or may be asked to have a full bladder during treatment to help push the small bowel out of the way. The amount of radiation may be adjusted to deliver lower amounts more evenly or higher amounts to specific areas. If a patient has surgery, clips may be placed at the tumor site to help show the area to be irradiated.