Gastrointestinal Complications

Summary Type: Supportive care
Summary Audience: Health professionals
Summary Language: English
Summary Description: Expert-reviewed information summary about constipation, impaction, bowel obstruction, and diarrhea as complications of cancer or its treatment. The management of these problems is discussed.

Gastrointestinal Complications


Gastrointestinal complications (constipation, impaction, bowel obstruction, diarrhea, and radiation enteritis) are common problems for oncology patients. The growth and spread of cancer, as well as its treatment, contribute to these conditions.

Constipation is the slow movement of feces through the large intestine that results in the passage of dry, hard stool. This can result in discomfort or pain.1 The longer the transit time of stool in the large intestine, the greater the fluid absorption and the drier and harder the stool becomes.

Functional disorders such as inactivity, immobility, or physical and social impediments (particularly inconvenient bathroom availability) can contribute to constipation. Depression and anxiety caused by cancer treatment or cancer pain can lead to constipation, either alone or with other functional and physiologic disorders. Perhaps the most common causes of constipation are inadequate fluid intake and pain medications; however, these causes are manageable.

Constipation may be annoying and uncomfortable, but fecal impaction can be life-threatening. Impaction refers to the accumulation of dry, hardened feces in the rectum or colon. The patient with a fecal impaction may present with circulatory, cardiac, or respiratory symptoms rather than with gastrointestinal symptoms.2 If the fecal impaction is not recognized, the signs and symptoms may progress and result in death.

In contrast to constipation or impaction, an intestinal obstruction is a partial or complete occlusion of the bowel lumen by a process other than fecal impaction. Intestinal obstructions can be classified by 3 means: the type of obstruction, the obstructing mechanism, and the part of the bowel involved.

Structural disorders, such as intraluminal and extraluminal bowel lesions caused by primary or metastatic tumor, postoperative adhesions, volvulus of the bowel, or incarcerated hernia, affect peristalsis and the maintenance of normal bowel function. These disorders can lead to total or partial obstruction of the bowel. Patients who have colostomies are at special risk of developing constipation. If stool is not passed on a regular basis (once a day to several times a day), further investigation is warranted. A partial or complete blockage may have occurred, particularly if no flatus has been passed.3,

Diarrhea can occur throughout the continuum of cancer care, and the effects can be physically and emotionally devastating. Although less prevalent than constipation, diarrhea remains a significant symptom burden for people with cancer. Diarrhea can alter dietary patterns, trigger dehydration, create electrolyte imbalance, impair function, cause fatigue, impair skin integrity, limit activity, and in some cases, be life threatening. Furthermore, diarrhea can lead to increased caregiver burden. Specific definitions of diarrhea vary widely. Acute diarrhea is generally considered to be an abnormal increase in stool liquid that lasts more than 4 days but less than 2 weeks. Another definition suggests that diarrhea is an increase in stool liquidity (>300 mL of stool) and frequency (the passage of >3 unformed stools) during a 24-hour period.4 Diarrhea is considered chronic when it persists longer than 2 months.

Radiation enteritis is a functional disorder of the large and small bowel that occurs during or after a course of radiation therapy to the abdomen, pelvis, or rectum.

The large and small bowel are very sensitive to ionizing radiation. Although the probability of tumor control increases with the radiation dose, so does the damage to normal tissues. Acute side effects to the intestines occur at approximately 1,000 cGy. Because curative doses for many abdominal or pelvic tumors range between 5,000 and 7,500 cGy, enteritis is likely to occur.5,

It should be noted that management of constipation, impaction, bowel obstruction, diarrhea, and radiation enteritis in the pediatric patient varies from the adult patient and should be adjusted accordingly.

1 Culhane B: Constipation. In: Yasko J, ed.: Guidelines for Cancer Care: Symptom Management. Reston, Va: Reston Publishing Company, Inc., 1983, pp 184-7.

2 Wright BA, Staats DO: The geriatric implications of fecal impaction. Nurse Pract 11 (10): 53-8, 60, 64-6, 1986.

3 Hampton BG, Bryant RA, eds.: Ostomies and Continent Diversions: Nursing Management. St. Louis, Mo: Mosby Year Book, Inc., 1992.

4 Tuchmann L, Engelking C: Cancer-related diarrhea. In: Gates RA, Fink RM, eds.: Oncology Nursing Secrets. 2nd ed. Philadelphia, Pa: Hanley and Belfus, 2001, pp 310-22.

5 Perez CA, Brady LW, eds.: Principles and Practice of Radiation Oncology. 3rd ed. Philadelphia, Pa: Lippincott-Raven Publishers, 1998.


Etiology of constipation

Common factors that contribute to the development of constipation in the general population are diet, altered bowel habits, inadequate fluid intake, and lack of exercise. Constipation can be a presenting symptom of cancer, or it can occur later as a side effect of a growing tumor or treatment of the tumor. For patients with cancer, additional causative factors are the tumor itself, cancer-related problems, the effects of drug therapy for cancer or for cancer pain, and other concurrent processes such as organ failure, decreased mobility, and depression.1 Physiologic factors include inadequate oral intake, dehydration, inadequate intake of dietary fiber, or organ failure. Any or all of these factors can occur because of the disease process, aging, debilitation, or treatment. (Refer to the Nausea, Vomiting, Constipation, and Bowel Obstruction in Advanced Cancer section in the PDQ summary on Nausea and Vomiting for more information.)

Causes of constipation

  • Insufficient fiber or bulk in diet.*
  • Inadequate fluid intake.*
    Altered bowel habits
  • Repeatedly ignoring defecation reflex.
  • Excessive use of laxatives and/or enemas.
    Prolonged immobility* and/or inadequate exercise
  • Spinal cord injury or compression, fractures, fatigue, weakness, or inactivity (including bedrest).
  • Intolerance with respiratory or cardiac problems.
  • Chemotherapy (e.g., any agent that can cause autonomic nervous system changes such as vinca alkaloids, oxaliplatins, taxanes, and thalidomide).*
  • Opioids or sedatives.
  • Anticholinergic preparations (e.g., gastrointestinal antispasmodics, antiparkinsonism agents, and antidepressants).
  • Phenothiazines.
  • Calcium- and aluminum-based antacids.
  • Diuretics.
  • Vitamin supplements (e.g., iron and calcium).
  • Tranquilizers and sleeping medications.
  • General anesthesia and pudendal blocks.
    Bowel disorders
  • Irritable colon, diverticulitis, or tumor.*
    Neuromuscular disorders (disruption of innervation leads to atony of the bowel)
  • Neurological lesions (cerebral tumors).
  • Spinal cord injury or compression.*
  • Paraplegia.
  • Cerebrovascular accident with paresis.
  • Weak abdominal muscles.
    Metabolic disorders
  • Hypothyroidism and lead poisoning.
  • Uremia.*
  • Dehydration.*
  • Hypercalcemia.*
  • Hypokalemia.
  • Hyponatremia.
  • Chronic illness.
  • Anorexia.
  • Immobility.
  • Antidepressants.
    Inability to increase intra-abdominal pressure
  • Emphysema.
  • Any neuromuscular impairment of the diaphragm or abdominal muscles.
  • Massive abdominal hernias.
    Atony of muscles
  • Malnutrition.
  • Cachexia, anemia, or carcinoma.*
  • Senility.
    Environmental factors
  • Inability to get to the bathroom without assistance.
  • Unfamiliar or hurried environment.
  • Excess heat leading to dehydration.
  • Change in bathroom habits (e.g., use of a bedpan).
  • Lack of privacy.
    Narrowing of colon lumen
  • Related to scarring from radiation therapy, surgical anastomosis, or compression from growth of extrinsic tumor.

*Frequently seen in oncology patients

Constipation is frequently the result of autonomic neuropathy caused by the vinca alkaloids, taxanes, and thalidomide. Other drugs such as opioid analgesics or anticholinergics (antidepressants and antihistamines) may lead to constipation by causing decreased sensitivity to the defecation reflexes and decreased gut motility. Since constipation is common with the use of opioids, a bowel regimen should be initiated at the time opioids are prescribed and continued for as long as the patient takes opioids. Opioids produce varying degrees of constipation, suggesting a dose-related phenomenon. One study suggests that clinicians should not base laxative prescribing on the opioid dose, but rather should titrate the laxative according to bowel function. Lower doses of opioids or weaker opioids, such as codeine, are just as likely to cause constipation.2 (Refer to the Side Effects of Opioids section in the PDQ summary on Pain for more information.)

Other diseases, such as diabetes (with autonomic neuropathy) and hypothyroidism, may cause constipation. Metabolic disorders, such as hypokalemia and hypercalcemia, also predispose cancer patients to developing constipation. Once these disorders are corrected, constipation should subside.1,

Assessment of constipation

A normal bowel pattern is having at least 3 stools per week and no more than 3 per day; however, these criteria may be inappropriate for cancer patients.1,3 Constipation should be viewed as a subjective symptom involving the complaints of decreased frequency with incomplete passage of dry, hard stool. A thorough history of the patient’s bowel pattern, diet changes, and medications along with a physical examination can identify possible causes of constipation. The evaluation should also include assessment of associated symptoms such as distention, flatus, cramping, or rectal fullness. A digital rectal examination should always be done to rule out fecal impaction at the level of the rectum. A test for occult blood will be helpful in determining a possible intraluminal lesion. A thorough examination of the gastrointestinal tract is necessary if cancer is suspected.4,

The following questions may provide a useful assessment guide:

  1. What is normal for the patient: frequency, amount, and timing?
  2. When was the last bowel movement? What was the amount, consistency, and color? Was blood passed with it?
  3. Has the patient been having any abdominal discomfort, cramping, nausea or vomiting, pain, excessive gas, or rectal fullness?
  4. Does the patient regularly use laxatives or enemas? What does the patient usually do to relieve constipation? Does it usually work?
  5. What type of diet does the patient follow? How much and what type of fluids are taken on a regular basis?
  6. What medication (dose and frequency) is the patient taking?
  7. Is this symptom a recent change?
  8. How many times a day is flatus passed?

Physical assessment will determine the presence or absence of bowel sounds, flatus, or abdominal distention. Patients with colostomies should also be assessed for constipation. Dietary habits, fluid intake, activity levels, and use of opioids in these patients should be assessed. Irrigation of the colostomy should be monitored for proper technique.

Management of constipation

Comprehensive management of constipation includes prevention (if possible), elimination of causative factors, and judicious use of laxatives. Some patients can be encouraged to increase dietary fiber (fruits; green, leafy vegetables; whole grain cereals; breads; and bran) and to increase fluid intake to one-half ounce per pound of body weight daily (if not contraindicated by renal or heart disease). A study that involved geriatric patients compared the efficacy, cost, and ease of administration of a natural laxative mixture (raisins, currants, prunes, figs, dates, and prune concentrate) with protocols using stool softeners, lactulose, and other laxatives. Results indicate lower costs, more natural and regular bowel movements, and increased ease of administration with natural laxatives. Even though generalization from these findings is limited by small sample size, additional exploration of natural laxatives in cancer patient populations might be useful.5 A program for prevention of constipation in cancer patients is described below.

Goal: Prevention of constipation with evacuation of at least 1 soft stool daily.

  • Establish the patient’s normal bowel pattern and habits (time of day for normal bowel movement, consistency, color, and amount).
  • Explore the patient’s level of understanding and compliance relating to exercise level, mobility, and diet (fluid, fruit, and fiber intake).
  • Determine normal or usual use of laxatives, stimulants, or enemas.
  • Determine laboratory values, specifically looking at platelet count.
  • Conduct a physical assessment of the rectum (or stoma) to rule out impaction.

Record bowel movements daily. Commonly used interventions include the following:

  • Encourage patient to increase fluid intake, with a goal of drinking eight 8-ounce (240 mL) glasses of fluid daily unless contraindicated.
  • Encourage regular exercise, including abdominal exercises in bed or moving from bed to chair if the patient is not ambulatory.
  • Experts recommend that healthy adults consume 20 to 35 g of fiber per day (average consumption is 11 g). While there are no specific fiber recommendations for cancer patients, they should also be encouraged to eat more high-fiber foods such as fruits (e.g., raisins, prunes, peaches, and apples), vegetables (e.g., squash, broccoli, carrots, and celery), and whole-grain cereals, breads, and bran. Increased fiber intake must be accompanied by increased fluid intake or constipation may result. High-fiber intake is contraindicated in patients at increased risk for bowel obstruction such as those with a history of bowel obstruction or status postcolostomy.
  • Provide a warm or hot drink approximately one-half hour before time of patient’s usual defecation.
  • Provide privacy and quiet time at the patient’s usual or planned time for defecation.
  • Provide toilet or bedside commode and appropriate assistive devices; avoid bedpan use whenever possible.
  • Start one of the following regimens if the patient has not had a stool in 3 days or on the first day that any patient starts taking drugs associated with constipation:
    • Stool softeners (e.g., docusate sodium, 1–2 capsules per day). For opioid-related constipation, stool softeners should be used in combination with a stimulant laxative. Bulk-producing agents are not recommended in a regimen used to counteract the bowel effects of opioids.
    • 2 tablets of a senna preparation twice daily.
    • 1 bisacodyl tablet at bedtime.
    • Milk of magnesia, 30 to 45 mL, if a bowel movement is not achieved in 24 hours after other methods are instituted.
  • If the amount of stool is still inadequate, increase stool softeners up to 6 capsules per day or a senna preparation (e.g., Senokot) gradually to a maximum of 8 tablets (4 tablets twice a day); bisacodyl may be increased gradually to 3 tablets.
  • If the amount of stool is still inadequate, a glycerin or bisacodyl suppository or enema (phosphate/biphosphate, oil retention, or tap water) should be used with caution, especially in patients with neutropenia or thrombocytopenia.

Medical management includes the administration of saline or chemical laxatives, suppositories, enemas, or agents that increase bulk.

Rectal agents should be avoided in cancer patients at risk for thrombocytopenia, leukopenia, and/or mucositis from cancer and its treatment. In the immunocompromised patient, no manipulation of the anus should occur, i.e., no rectal examinations, no suppositories, and no enemas. These actions can lead to the development of anal fissures or abscesses, which are portals of entry for infection. Also, the stoma of a patient with neutropenia should not be manipulated.

Medical agents for constipation

    Bulk producers
  • Bulk producers are natural or semisynthetic polysaccharide and cellulose. They work with the body’s natural processes to hold water in the intestinal tract, soften the stool, and increase the frequency of the passage of stool. Bulk producers are not recommended for use in a regimen to counteract the bowel effects of opioids.
  • Onset: 12 to 24 hours (may be delayed up to 72 hours).
  • Caution: Patients should take with 2 full 8-oz (240 mL) glasses of water and maintain adequate hydration to avoid the risk of developing a bowel obstruction. Avoid administering psyllium with salicylates, nitrofurantoin, and digitalis because psyllium decreases the actions of these drugs. Avoid use if intestinal obstruction is suspected.
  • Use: Effective in managing irritable bowel syndrome.
  • Drugs and dosages:
    • methylcellulose (Cologel): 5 to 20 cc 3 times per day with water.
    • barley malt extract (Maltsupex): 4 tablets with meals and at bedtime or 2 tbsp powder or liquid 2 times per day for 3 to 4 days, then 1 to 2 tbsp at bedtime.
    • psyllium: varies from 1 tbsp to 1 packet, depending on brand, 1 to 3 times per day.
    • Fiber-Malt: 1 tbsp 2 or 3 times daily; 1 to 3 times daily for children aged 4 to 12 years; not to be given to children younger than 4 years.
    Saline laxatives
  • The high osmolarity of the compounds in saline laxatives attracts water into the lumen of the intestines. The fluid accumulation alters the stool consistency, distends the bowel, and induces peristaltic movement. Cramps may occur.
  • Onset: 0.5 to 3 hours.
  • Caution: Repeated use can alter fluid and electrolyte balance. Avoid magnesium-containing laxatives in patients with renal dysfunction. Avoid sodium-containing laxatives in patients with edema, congestive heart failure, megacolon, or hypertension.
  • Use: Mostly as a bowel preparation to clear the bowels for rectal or bowel examinations.
  • Drugs and dosages:
    • magnesium sulfate: 15 g in a glass of water.
    • milk of magnesia: 10 to 20 cc if concentrated, 15 to 30 cc if regular.
    • magnesium citrate: 240 cc.
    • sodium phosphate: 4 to 8 g dissolved in water.
    • monobasic and dibasic sodium phosphate (Fleet Phospho-soda): 20 to 40 mL mixed with 4 oz cold water.
    Stimulant laxatives
  • Stimulant laxatives increase motor activity of the bowels by direct action on the intestines.
  • Onset: 6 to10 hours.
  • Caution: Prolonged use of these drugs causes laxative dependency and loss of normal bowel function. Prolonged use of danthron discolors rectal mucosa and discolors alkaline urine red. Bisacodyl must be excreted in bile to be active and is not effective with biliary obstruction or diversion. Avoid bisacodyl with known or suspected ulcerative lesions of the colon. These medications may cause cramping.
  • Drug interactions: Avoid taking bisacodyl within 1 hour of taking antacids, milk, or cimetidine because they cause premature dissolving of the enteric coating, which results in gastric or duodenal stimulation. There is an increased absorption of danthron when it is given with docusate.
  • Use: To evacuate bowel for rectal or bowel examinations. Most of the stimulant laxatives act on the colon.
  • Drugs and dosages:
    • danthron: 37.5 to 150 mg with evening meal or 1 hour after evening meal.
    • calcium salts of sennosides: 12 to 24 mg at bedtime; senna: Senolax, Seneson, or Black-Draught (2 tablets); Senokot (2 tablets or 10–15 cc at bedtime).
    • bisacodyl: 10 to 15 mg swallowed whole, not chewed, or a 10-mg suppository.
    Lubricant laxatives
  • Lubricant laxatives lubricate intestinal mucosa and soften stool.
  • Caution: Administer on empty stomach at bedtime. Mineral oil prevents absorption of oil-soluble vitamins and drugs. With older patients, aspiration potential suggests that mineral oil should be avoided because it can cause lipid pneumonitis. It can interfere with postoperative healing of anorectal surgery. Avoid giving with docusate sodium. Docusate sodium causes increased systemic absorption of mineral oil.
  • Use: Prophylactically to prevent straining in patients for whom straining would be dangerous.
  • Drugs and dosages:
    • mineral oil: 5 to 30 cc at bedtime.
    Fecal softeners
  • Fecal softeners promote water retention in the fecal mass, thus softening the stool. Up to 3 days may pass before an effect is noted. Stool softeners and emollient laxatives are of limited use because of colonic resorption of water from the forming stool.
  • Fecal softeners should not be used as the sole regimen but may be useful given in combination with stimulant laxatives.
  • Caution: May increase the systemic absorption of mineral oil when administered together.
  • Use: Prophylactically to prevent straining. Most beneficial when stool is hard.
  • Drugs and dosages:
    • docusate sodium: 50 to 240 mg taken with a full glass of water.
    • docusate calcium: 240 mg each day until bowel movement is normal.
    • docusate potassium: 100 to 300 mg each day until bowel movement is normal; should increase daily fluid intake.
    • Poloxamer 188: 188 mg (480 mg at bedtime).
    Lactulose (Cholac, Cephulac)
  • Lactulose is a synthetic disaccharide that passes to the colon undigested. When it is broken down in the colon, it produces lactic acid, formic acid, acetic acid, and carbon dioxide. These products increase the osmotic pressure, thus increasing the amount of water held in the stool, which softens the stool and increases the frequency of passage.
  • Onset: 24 to 48 hours.
  • Caution: Excessive amounts may cause diarrhea with electrolyte losses. Avoid giving to patients with acute abdomen, fecal impaction, or obstruction.
  • Dosage: 15 to 30 cc each day (contains 10–20 g of lactulose).
    Polyethylene glycol and electrolytes (Golytely, Colyte)
  • Five packets are mixed with 1 gallon (3.785 liters) of tap water and contain the following: polyethylene glycol (227.1 g), sodium chloride (5.53 g), potassium chloride (2.82 g), sodium bicarbonate (6.36 g), and sodium sulfate (anhydrous, 21.5 g). Do not add flavorings. Serve chilled to improve palatability. Can be stored up to 48 hours in the refrigerator.
  • Use: To clear bowel with minimal water and sodium loss or gain.

1 Portenoy RK: Constipation in the cancer patient: causes and management. Med Clin North Am 71 (2): 303-11, 1987.

2 Bennett M, Cresswell H: Factors influencing constipation in advanced cancer patients: a prospective study of opioid dose, dantron dose and physical functioning. Palliat Med 17 (5): 418-22, 2003.

3 McShane RE, McLane AM: Constipation. Consensual and empirical validation. Nurs Clin North Am 20 (4): 801-8, 1985.

4 Bruera E, Suarez-Almazor M, Velasco A, et al.: The assessment of constipation in terminal cancer patients admitted to a palliative care unit: a retrospective review. J Pain Symptom Manage 9 (8): 515-9, 1994.

5 Beverley L, Travis I: Constipation: proposed natural laxative mixtures. J Gerontol Nurs 18 (10): 5-12, 1992.


Etiology of impaction

Five major factors precipitate impaction:

  • Opioid analgesics.
  • Prolonged inactivity.
  • Dietary alterations.
  • Psychiatric illness.
  • Chronic use of drugs for constipation.1

    Laxatives used to decrease constipation are the drugs that contribute most to the development of constipation and impaction. Repeated and escalating dosing of laxatives renders the colon less sensitive to its intrinsic reflexes stimulated by distention. (Refer to the Etiology of Constipation section of this summary for causes of constipation that may lead to impaction.)

Signs and symptoms of impaction

The patient may exhibit symptoms similar to constipation or present with symptoms unrelated to the gastrointestinal system. If the impaction presses on the sacral nerves, the patient may experience back pain. If the impaction presses on the ureters, bladder, or urethra, urinary symptoms can develop. These symptoms include increased or decreased frequency or urgency of urination, or urinary retention.

When abdominal distention occurs, movement of the diaphragm is compromised, leading to insufficient aeration with subsequent hypoxia and left ventricular dysfunction. Hypoxia can, in turn, precipitate angina or tachycardia. If the vasovagal response is stimulated by the pressure of impaction, the patient may become dizzy and hypotensive.

Movement of stool around the impaction may result in diarrhea, which can be explosive. Coughing or activities that increase intra-abdominal pressure may cause leakage of stool. The leakage may be accompanied by nausea, vomiting, abdominal pain, and dehydration and is virtually diagnostic of the condition. Thus, the patient with an impaction may present in an acutely confused and disoriented state, with signs of tachycardia, diaphoresis, fever, elevated or low blood pressure, and/or abdominal fullness or rigidity.

Assessment of impaction

Assessment includes the questions discussed previously for the patient with constipation (refer to the Assessment of Constipation section of this summary for the list of questions). Additional assessment includes auscultation of bowel sounds to determine if they are present, absent, hyperactive, or hypoactive. The abdomen should be inspected for distention and gently palpated for any masses, rigidity, or tenderness. A rectal examination will determine the presence of stool in the rectum or sigmoid colon. An abdominal x-ray (flat and upright) would show loss of haustral markings, gas patterns reflecting gross amounts of stool, and dilatation proximal to the impaction.2,

If a diagnosis of fecal impaction is uncertain, a laboratory workup can rule out other problems. A complete blood cell count, appropriate blood chemistries, chest x-ray, and an electrocardiogram can be performed. If the patient has become dehydrated, the blood urea nitrogen, creatinine, and serum osmolality will be elevated. There may be an elevation of the hemoglobin and hematocrit indicating hemoconcentration. The white blood cell (WBC) count may be slightly elevated in the presence of a fever. If the WBC count is extremely elevated and the patient is exhibiting a high fever and abdominal pain, an obstruction, perforation, infection, or inflammatory process must be ruled out. With marked distention of the cecum (diameter ≥12 cm), there is a risk of bowel perforation.

Treatment of impaction

The primary treatment of impaction is to hydrate and soften the stool so that it can be removed or passed. Enemas (oil retention, tap water, or hypertonic phosphate) lubricate the bowel and soften the stool. Caution must be exercised; fecal impaction can irritate the bowel wall, and enemas in excess may perforate the bowel. The patient may need to be digitally disimpacted if the stool is within reach. This is best done after administering an enema to lubricate the bowel.

Nonstimulating bowel softeners such as docusate can be used to help soften stool higher in the colon. Mineral or olive oil can be given to loosen the stool. Caution should be used when giving docusate sodium with mineral oil because there could be an increased systemic absorption of the mineral oil leading to systemic lipid granulomas.3 Glycerin suppositories can also be used. Any laxatives that might stimulate the bowel or cause cramping should be avoided so that the bowel is not damaged further.

1 Cefalu CA, McKnight GT, Pike JI: Treating impaction: a practical approach to an unpleasant problem. Geriatrics 36 (5): 143-6, 1981.

2 Bruera E, Suarez-Almazor M, Velasco A, et al.: The assessment of constipation in terminal cancer patients admitted to a palliative care unit: a retrospective review. J Pain Symptom Manage 9 (8): 515-9, 1994.

3 Brandt LJ: Gastrointestinal Disorders of the Elderly. New York, NY: Raven Press, 1984.

Large or Small Bowel Obstruction

There are 4 types of obstruction:

  1. Simple.
  2. Closed-loop.
  3. Strangulated.
  4. Incarcerated.

A simple obstruction is blocked in 1 place; a closed-loop obstruction is blocked in 2 places. A closed-loop obstruction may develop when the bowel twists around on itself, isolating the looped section of the bowel and obstructing the portion above it. With a strangulated obstruction, there is decreased blood flow to the bowel that, if not relieved, will develop into an incarcerated obstruction, and the bowel will become necrotic.

The obstructing mechanism can be mechanical or nonmechanical. Mechanical factors can be anything that causes a narrowing of the intestinal lumen (e.g., inflammation or trauma to the bowel, neoplasms, adhesions, hernias, volvulus, or a compression from outside the intestinal tract).1 Nonmechanical factors include those that interfere with the muscle action or innervation of the bowel: paralytic ileus, mesenteric embolus or thrombus, and hypokalemia.

Eighty percent of bowel obstructions occur in the small intestine; the other 20% occur in the colon.2 Bowel obstructions are frequently seen in the ileum. Small bowel obstructions are caused often by adhesions or hernias, whereas large bowel obstructions are caused by carcinomas, volvulus, or diverticulitis. The presentation of obstruction will relate to whether the small or large intestine is involved.

Etiology of bowel obstruction

The most common malignancies that cause bowel obstruction are cancers of the colon, stomach, and ovary. Extra-abdominal cancers (such as lung and breast cancers and melanoma) can spread to the abdomen, causing bowel obstruction.3 Patients who have had abdominal surgery or abdominal radiation are also at higher risk of developing bowel obstruction.2 Bowel obstructions are most common during advanced stages of disease.

Assessment and diagnosis of bowel obstruction

Examination of the patient will determine the presence or absence of abdominal pain, vomiting, and evidence of the passage of flatus or stool. A complete blood cell count, electrolyte panel, and urinalysis are obtained to evaluate fluid and electrolyte imbalance and/or sepsis. An elevated white blood cell count (15,000–20,000/mm3) suggests bowel necrosis. Flat and upright abdominal films as well as a barium enema may be necessary to determine where the obstruction is located. While it remains controversial, an upper gastrointestinal series is contraindicated with an acutely presenting obstruction because it can cause a partial obstruction to become complete or may further complicate a total obstruction. If the patient is exhibiting dehydration, oliguria, or shock, perforation of the bowel may have occurred, and immediate medical or surgical intervention is indicated. (Refer to the Nausea, Vomiting, Constipation, and Bowel Obstruction in Advanced Cancer section in the PDQ summary on Nausea and Vomiting for more information.)

Treatment of acute bowel obstruction

Careful serial examinations are necessary in the management of patients with progressive abdominal symptoms that may be due to acute bowel obstruction. The principles of supportive care in this setting include volume resuscitation, correction of electrolyte imbalances, and transfusion support (if necessary). These measures should precede or accompany decompression efforts.

When bowel obstruction is partial, decompression of the distended bowel may be attempted with nasogastric or intestinal tubes. Although use of these tubes may be successful in reducing edema, relieving fluid and gas accumulation, or decreasing the need for multiple stage procedures,4 surgery may be necessary within 24 hours if there is complete, acute obstruction. The use of self-expandable stents to decompress complete, acute malignant bowel obstruction has been noted to decrease the frequency of unnecessary surgery by permitting staging of the disease, increasing the rate of primary anastomosis relative to colostomy, and decreasing morbidity in patients with left-sided colon and rectal malignancies. Further study is warranted including cost analysis.5,

Management of chronic, malignant bowel obstruction

Patients with advanced cancer may have chronic, progressive bowel obstruction that is inoperable.6,7 The most frequent causes of inoperability are extensive tumor and multiple partial obstructions.8,9,10 A retrospective review evaluating surgical palliation of malignant bowel obstruction secondary to peritoneal carcinomatosis in 63 patients with nongynecological cancer used the ability to tolerate solid food at hospital discharge as the criterion for successful palliation. Multiple logistic regression analysis identified the absence of ascites and obstruction not involving the small bowel as predictors of successful surgical palliation in this population. Successful palliation was achieved in 45% of patients and was maintained in 76% of this group at a median follow-up of 78 days, for an overall success rate of 35%. Postoperative mortality was 15%, and postoperative complications occurred in 44%.11

For some patients with malignant obstructions of the gastrointestinal tract, the use of expandable metal stents may provide palliation of obstructive symptoms. Available stents include esophageal, biliary, gastroduodenal, and colorectal.5,12,13,14,15,16,17 Stents may be placed under endoscopic guidance, with or without fluoroscopy, or by an interventional radiologist using fluoroscopy. Morbidity with stent placement may be lower than with surgery. Adequate imaging of the stricture itself and the gastrointestinal tract distal to the stricture is recommended to assess stricture length, detect multifocal disease, and determine the appropriateness of stenting.18,19,20,.

When neither surgery nor stenting is possible, the accumulation of the unabsorbed secretions produce nausea, vomiting, pain, and colicky activity as a consequence of the partial or complete occlusion of the lumen. In this case, a gastrostomy tube is commonly used to provide decompression of air and fluid that may be accumulating and causing visceral distention and pain. The gastrostomy tube is placed into the stomach and is attached to a drainage bag that can be easily concealed under clothing. When the valve between the gastrostomy tube and the bag is open, the patient may be able to eat or drink by mouth without creating discomfort since the food is drained directly into the bag. Dietary discretion is advised to minimize the risk of tube obstruction by solid food. If the obstruction improves, the valve can be closed and the patient may once again benefit from enteral nutrition.

Sometimes, decompression is difficult even with a gastrostomy tube in place. This may be due to the accumulation of fluid, since several liters per day of gastrointestinal secretions may be produced. To relieve continuous abdominal pain, opioid analgesics via continuous subcutaneous or intravenous infusion may be necessary. Effective antispasmodics in this situation include anticholinergics (such as hyoscine butylbromide) 21 and possibly corticosteroids as well as centrally acting agents. If the bowel obstruction is thought to be functional (rather than mechanical) in origin, metoclopramide is the drug of choice due to its prokinetic effects on the bowel. For complete bowel obstruction thought to be irreversible, a trial of an antispasmodic such as hyoscyamine may decrease bowel contractions and therefore yield pain relief. Another option for management of refractory pain and/or nausea is the synthetic somatostatinanalog octreotide. This agent inhibits the release of several gastrointestinal hormones and reduces gastrointestinal secretions.22,23,24 Octreotide is usually given subcutaneously at 50 to 200 µg 3 times per day and may reduce the nausea, vomiting, and abdominal pain of malignant bowel obstruction. For selected patients, the addition of an anticholinergic such as scopolamine may be helpful in reducing the associated painful colic of malignant bowel obstruction when octreotide alone is ineffective. When either scopolamine or octreotide is used alone, each is ineffective.12,25,26,27 Corticosteroids are widely used in treating bowel obstruction, but empirical support is limited.28 They may be useful as adjuvant antiemetics and analgesics in this setting given as dexamethasone at a starting dose of 6 to 10 mg subcutaneously or intravenously 3 to 4 times per day.12,25 (Refer to the Nausea, Vomiting, Constipation, and Bowel Obstruction in Advanced Cancer section in the PDQ summary on Nausea and Vomiting for more information.)

1 Givens BA, Simmons SJ: Gastroenterology in Clinical Nursing. 4th ed. St. Louis, Mo: C.V. Mosby Co, 1984.

2 Bouchier IA: Gastroenterology. 3rd ed. London: Balliere Tindall, 1982.

3 Ripamonti C, De Conno F, Ventafridda V, et al.: Management of bowel obstruction in advanced and terminal cancer patients. Ann Oncol 4 (1): 15-21, 1993.

4 Horiuchi A, Maeyama H, Ochi Y, et al.: Usefulness of Dennis Colorectal Tube in endoscopic decompression of acute, malignant colonic obstruction. Gastrointest Endosc 54 (2): 229-32, 2001.

5 Martinez-Santos C, Lobato RF, Fradejas JM, et al.: Self-expandable stent before elective surgery vs. emergency surgery for the treatment of malignant colorectal obstructions: comparison of primary anastomosis and morbidity rates. Dis Colon Rectum 45 (3): 401-6, 2002.

6 Ripamonti C, Bruera E: Palliative management of malignant bowel obstruction. Int J Gynecol Cancer 12 (2): 135-43, 2002 Mar-Apr.

7 Potluri V, Zhukovsky DS: Recent advances in malignant bowel obstruction: an interface of old and new. Curr Pain Headache Rep 7 (4): 270-8, 2003.

8 Jung GS, Song HY, Kang SG, et al.: Malignant gastroduodenal obstructions: treatment by means of a covered expandable metallic stent-initial experience. Radiology 216 (3): 758-63, 2000.

9 Camúñez F, Echenagusia A, Simó G, et al.: Malignant colorectal obstruction treated by means of self-expanding metallic stents: effectiveness before surgery and in palliation. Radiology 216 (2): 492-7, 2000.

10 Coco C, Cogliandolo S, Riccioni ME, et al.: Use of a self-expanding stent in the palliation of rectal cancer recurrences. A report of three cases. Surg Endosc 14 (8): 708-11, 2000.

11 Blair SL, Chu DZ, Schwarz RE: Outcome of palliative operations for malignant bowel obstruction in patients with peritoneal carcinomatosis from nongynecological cancer. Ann Surg Oncol 8 (8): 632-7, 2001.

12 Baron TH: Expandable metal stents for the treatment of cancerous obstruction of the gastrointestinal tract. N Engl J Med 344 (22): 1681-7, 2001.

13 Law WL, Chu KW, Ho JW, et al.: Self-expanding metallic stent in the treatment of colonic obstruction caused by advanced malignancies. Dis Colon Rectum 43 (11): 1522-7, 2000.

14 Repici A, Reggio D, De Angelis C, et al.: Covered metal stents for management of inoperable malignant colorectal strictures. Gastrointest Endosc 52 (6): 735-40, 2000.

15 Harris GJ, Senagore AJ, Lavery IC, et al.: The management of neoplastic colorectal obstruction with colonic endolumenal stenting devices. Am J Surg 181 (6): 499-506, 2001.

16 Aviv RI, Shyamalan G, Watkinson A, et al.: Radiological palliation of malignant colonic obstruction. Clin Radiol 57 (5): 347-51, 2002.

17 Dauphine CE, Tan P, Beart RW Jr, et al.: Placement of self-expanding metal stents for acute malignant large-bowel obstruction: a collective review. Ann Surg Oncol 9 (6): 574-9, 2002.

18 Lopera JE, Alvarez O, Castaño R, et al.: Initial experience with Song's covered duodenal stent in the treatment of malignant gastroduodenal obstruction. J Vasc Interv Radiol 12 (11): 1297-303, 2001.

19 Razzaq R, Laasch HU, England R, et al.: Expandable metal stents for the palliation of malignant gastroduodenal obstruction. Cardiovasc Intervent Radiol 24 (5): 313-8, 2001 Sep-Oct.

20 Baron TH, Rey JF, Spinelli P: Expandable metal stent placement for malignant colorectal obstruction. Endoscopy 34 (10): 823-30, 2002.

21 De Conno F, Caraceni A, Zecca E, et al.: Continuous subcutaneous infusion of hyoscine butylbromide reduces secretions in patients with gastrointestinal obstruction. J Pain Symptom Manage 6 (8): 484-6, 1991.

22 Ripamonti C, Mercadante S, Groff L, et al.: Role of octreotide, scopolamine butylbromide, and hydration in symptom control of patients with inoperable bowel obstruction and nasogastric tubes: a prospective randomized trial. J Pain Symptom Manage 19 (1): 23-34, 2000.

23 Fallon MT: The physiology of somatostatin and its synthetic analogue, octreotide. European Journal of Palliative Care 1 (1): 20-2, 1994.

24 Mystakidou K, Tsilika E, Kalaidopoulou O, et al.: Comparison of octreotide administration vs conservative treatment in the management of inoperable bowel obstruction in patients with far advanced cancer: a randomized, double- blind, controlled clinical trial. Anticancer Res 22 (2B): 1187-92, 2002 Mar-Apr.

25 Mercadante S: Assessment and management of mechanical bowel obstruction. In: Portenoy RK, Bruera E, eds.: Topics in Palliative Care. Volume 1. New York, NY: Oxford University Press, 1997, pp. 113-30.

26 Fainsinger RL: Integrating medical and surgical treatments in gastrointestinal, genitourinary, and biliary obstruction in patients with cancer. Hematol Oncol Clin North Am 10 (1): 173-88, 1996.

27 Ripamonti C, Panzeri C, Groff L, et al.: The role of somatostatin and octreotide in bowel obstruction: pre-clinical and clinical results. Tumori 87 (1): 1-9, 2001 Jan-Feb.

28 Feuer DJ, Broadley KE: Systematic review and meta-analysis of corticosteroids for the resolution of malignant bowel obstruction in advanced gynaecological and gastrointestinal cancers. Systematic Review Steering Committee. Ann Oncol 10 (9): 1035-41, 1999.


The reported prevalence and severity of diarrhea vary greatly. Some chemotherapeutic regimens are associated with diarrhea rates as high as 50% to 80%, particularly those containing fluoropyrimidines or irinotecan.1,2 Diarrhea is also commonly observed in patients diagnosed with carcinoid tumors, receiving radiation therapy to abdominal/pelvic fields, or undergoing bone marrow transplantation or surgical intervention of the gastrointestinal tract.3 In a large heterogeneous sample of cancer patients in various stages of treatment, the prevalence of moderate-to-severe diarrhea was 14%.4 Diarrhea occurs in approximately 7% to 10% of cancer patients upon admission to hospice.5 Among children with cancer during the last month of life, 19% experienced diarrhea.6,

The consequences of diarrhea can be significant and life-threatening. According to the National Cancer Institute's (NCI's) Common Toxicity Criteria, more than half of patients receiving chemotherapy for colorectal cancer experienced diarrhea of grade 3 (severe) or grade 4 (life-threatening), requiring treatment changes or the reduction, delay, or discontinuation of therapy (see the National Cancer Institute's Common Toxicity Criteria for Grading Severity of Diarrhea table).7,8 A review of several clinical trials of irinotecan plus high-dose fluorouracil and leucovorin in colorectal cancer revealed early death rates of 2.2% to 4.8%, primarily due to gastrointestinal toxicity.9 With the advent of more aggressive anticancer therapies, the potential physical and psychosocial consequences of diarrhea and its indirect effect on cancer treatment outcome are likely to expand.10,

Etiology of diarrhea

In patients being treated for cancer, diarrhea is most commonly induced by therapy.11 Conventional methods of diarrhea-causing treatment include surgery, chemotherapy, radiation therapy, and bone marrow transplantation. Other causes of acute diarrhea include antibiotic therapy, stress and anxiety associated with cancer diagnosis and treatment, and infection.12 Typical infections are of viral, bacterial, protozoan, parasitic, or fungal etiology; they may also be caused by pseudomembranous colitis, a cause of diarrhea that often does not respond to treatment.3 Clostridium difficile is a common cause of pseudomembranous colitis. Other causes of diarrhea in patients with cancer include the underlying cancer, responses to diet, or concomitant diseases (see the Possible Contributions to Diarrhea in Cancer table). Common causes of diarrhea in patients receiving palliative care are difficulty adjusting the laxative regimen and impaction leading to leakage of stool around the fecal obstruction.

Another strategy for categorizing the causes of diarrhea is by putative underlying mechanisms. These include exudative (i.e., excess blood or mucous enters the gastrointestinal tract), malabsorptive, dysmotile, osmotic, and secretory (due to increased secretion of electrolytes and fluid—probably the mechanism underlying chemotherapy-induced diarrhea), or combinations of these factors.13,

Surgery, a primary treatment modality for many cancers, can affect the body by mechanical, functional, and physiological alterations. Postsurgical complications of gastrointestinal surgery affecting normal bowel function that may contribute to diarrhea include increased transit time, gastroparesis, fat malabsorption, lactose intolerance, fluid and electrolyte imbalance, and dumping syndrome.14,15,

Certain chemotherapeutic agents can alter normal absorption and secretion functions of the small bowel, resulting in treatment-related diarrhea.7 Examples of chemotherapy agents with diarrhea-related potential are listed in the table below. Patients receiving concomitant abdominal or pelvic radiation therapy or recovering from recent gastrointestinal surgery will often experience more severe diarrhea.

Radiation therapy to abdominal, pelvic, lumbar, or para-aortic fields can result in changes to normal bowel function. Factors contributing to the occurrence and severity of intestinal complications depend on total dose, fractionation, volume of bowel irradiated, and concomitant chemotherapy. Common side effects of intestinal enteritis include diarrhea, malabsorption, gas, bloating, and cramping. Acute intestinal side effects occur at approximately 1,000 cGy and may last up to 8 to 12 weeks posttherapy. Chronic radiation enteritis may present months to years after completion of therapy and necessitates dietary modification and pharmacological management and, in some instances, surgical intervention (see the section Radiation Enteritis).

Graft-versus-host disease (GVHD) is a major complication of allogeneic transplantation, and the intestinal tract, skin, and liver are commonly affected. Symptoms of gastrointestinal GVHD include nausea and vomiting, severe abdominal pain and cramping, and watery, green diarrhea.16 The volume of accompanying GVHD-associated diarrhea may reach up to 10 liters per day and is an indicator of the degree and extent of mucosal damage.17 Acute GVHD is usually manifested within 100 days posttransplant, although it can occur as early as 7 to 10 days after transplant. It may resolve or develop into a chronic form requiring long-term treatment and dietary management.

Possible Contributions to Diarrhea in Cancer

Cancer-related 5,18,Carcinoid syndromeColon cancerLymphomaMedullary carcinoma of the thyroidPancreatic cancer, particularly islet cell tumors (Zollinger-Ellison syndrome)PheochromocytomaSurgery- or procedure-related 14,Celiac plexus blockCholecystectomy, esophagogastrectomyGastrectomy, pancreaticoduodenectomy (Whipple procedure)Intestinal resection (malabsorption due to short bowel syndrome)VagotomyChemotherapy-related 19,20,Capecitabine, cisplatin, cytosine arabinoside, cyclophosphamide, daunorubicin, docetaxel, doxorubicin, 5-fluorouracil, interferon, irinotecan, leucovorin, methotrexate, oxaliplatin, paclitaxel, topotecanRadiation therapy–related (refer to the Radiation Enteritis section of this summary) 21,22, Irradiation to the abdomen, para-aortics, lumbar, and pelvisBone marrow transplantation–related 23,Conditioning chemotherapy, total-body irradiation, graft-versus-host disease after allogeneic bone marrow or peripheral blood stem cell transplantsDrug adverse effects 5,18,Antibiotics, magnesium-containing antacids, antihypertensives, colchicine, digoxin, iron, lactulose, laxatives, methyldopa, metoclopramide, misoprostol, potassium supplements, propanolol, theophyllineConcurrent disease 5,18,Diabetes, hyperthyroidism, inflammatory bowel disease (Crohn’s disease, diverticulitis, gastroenteritis, HIV/AIDS, ulcerative colitis), obstruction (tumor-related)Infection 24,Clostridium difficile, Clostridium perfringens, Bacillus cereus, Giardia lamblia, Cryptosporidium, Salmonella, Shigella, Campylobacter, Rotavirus Fecal impaction 5,18,Constipation leading to obstructionDiet 5,18,Alcohol, milk, and dairy products (particularly in patients with lactose intolerance)Caffeine-containing products (coffee, tea, chocolate), specific fruit juices (prune juice, unfiltered apple juice, sauerkraut juice)High-fiber foods (raw fruits and vegetables, nuts, seeds, whole-grain products, dried legumes); high-fat foods (deep fat–fried foods, high-fat containing foods)Lactulose intolerance or food allergiesSorbitol-containing foods (candy and chewing gum); hot and spicy foods; gas-forming foods and beverages (cruciferous vegetables, dried legumes, melons, carbonated beverages)Psychological factors 18,Stress


Because of the potentially life-threatening nature of diarrhea, rapid, yet thorough, assessment is imperative. Few standardized assessment tools are available, and studies suggest that, as a result, standardized assessment is rare in the clinical setting.3 For a complete assessment, one author suggests obtaining background information from the patient that includes the type and extent of the patient’s cancer, anticancer treatment, comorbid factors, coexisting symptoms, patient and provider perceptions, as well as a thorough description of the diarrhea. Stringent monitoring conducted at least weekly is indicated during therapy using chemotherapeutic agents known to cause diarrhea.9 The NCI’s Common Toxicity Criteria evaluate diarrhea by number of stools per day, need for parenteral support, nocturnal stools, incontinence, and hemodynamic collapse.8,

National Cancer Institute’s Common Toxicity Criteria for Grading Severity of Diarrhea

Toxicity01234Patients without a colostomyNoneIncrease of <4 stools/day over pretreatmentIncrease of 4–6 stools/day or nocturnal stoolsIncrease of ≥7 stools/day >10 stools/dayNoneNoneModerate cramping, not interfering with normal activitySevere cramping and incontinence, interfering with daily activitiesGrossly bloody diarrhea and need for parenteral supportPatients with a colostomyNoneMild increase in loose, watery colostomy output compared with pretreatmentModerate increase in loose, watery colostomy output compared with pretreatment, but not interfering with normal activitySevere increase in loose, watery colostomy output compared with pretreatment, interfering with normal activityPhysiological consequences requiring intensive care; hemodynamic collapseFor patients undergoing bone marrow transplant (BMT)None>500 mL to ≤1,000 mL of diarrhea/day>1,000 mL to ≤1,500 mL of diarrhea/day>1,500 mL of diarrhea/daySevere abdominal pain with or without ileusFor children undergoing BMTNone >5 mL/kg to ≤10 mL/kg of diarrhea/day>10 mL/kg to ≤15 mL/kg of diarrhea/day>15 mL/kg of diarrhea/daySevere abdominal pain with or without ileus

The history also should include questions regarding the frequency of bowel movements during the past 24 hours, the character of the fecal material, and the time course of the development of diarrhea.25 One author has developed a visual tool to assist patients and families in characterizing the consistency of the stool.26 Six diagrams illustrate fecal material consistency ranging from well-formed, formed, and semiformed to loose, very loose, and liquid. Patients should be questioned regarding related symptoms that might indicate hemodynamic compromise or the underlying etiology. Specifically, questions should include information about dizziness, orthostatic symptoms, lethargy, cramping, abdominal pain, nausea, vomiting, fever, and rectal bleeding. These symptoms should be classified as complicated or uncomplicated, with therapy based on these classifications.27 Uncomplicated symptoms include grade 1 or 2 diarrhea with no other signs or symptoms. Management is conservative. Complicated symptoms include grade 1 or 2 diarrhea with any one of the following risk factors: moderate to severe cramping, grade 2 or higher nausea/vomiting (see table below), decreased performance status, fever, sepsis, neutropenia, frank bleeding, or dehydration. Grade 3 or 4 diarrhea is also classified as complicated. Thorough evaluation and close monitoring is warranted.27 The time course of diarrhea and concomitant symptom development are key to determining underlying etiology.25 Medication and dietary intake, as well as a history of recent travel, may provide additional clues regarding etiology. Weight loss and reduced urine output provide additional data regarding the severity of the effects of diarrhea.

Criteria for Grading Severity of Nausea and Vomiting

Grade 1Grade 2Grade 3Grade 4Grade 5Adapted from Cancer Therapy Evaluation Program, Common Terminology Criteria for Adverse Events, Version 3.0, DCTD, NCI, NIH, DHHS.NauseaLoss of appetite without alteration in eating habitsOral intake decreased without significant weight loss, dehydration or malnutrition; IV fluids indicated <24 hrsInadequate oral caloric or fluid intake; IV fluids, tube feedings, or TPN indicated ≥24 hrsLife-threatening consequencesDeathVomiting1 episode in 24 hrs2–5 episodes in 24 hrs; IV fluids indicated <24 hrs≥6 episodes in 24 hrs; IV fluids, or TPN indicated ≥24 hrsLife-threatening consequencesDeath

The goal of physical examination is to identify potential causes of diarrhea and its complications as quickly as possible to reduce morbidity. The physical examination should include vital signs and evaluation of skin turgor and oral mucosa to assess hemodynamic status and de