Diarrhea and cancer

ALSO KNOWN AS: Dysentery, intestinal flu

RELATED CONDITIONS: Colorectal cancer, gastrointestinal disease, pancreatic cancer

DEFINITION: Diarrhea is the passage of frequent loose or liquid stools. Diarrhea is usually characterized by the passage of loose stools more than three to four times in one day.

Risk factors: Diarrhea may occur as a result of cancer treatment, such as chemotherapy or other cancer medications; radiation therapy to the pelvis, rectum, or abdomen; or surgery. The chemotherapy drugs 5-fluorouracil (5FU), capecitabine, and irinotecan are particularly known to cause diarrhea, as are the drug therapy tyrosine kinase inhibitors. Diarrhea may be the result of an underlying condition, including central nervous system disorders, bowel obstruction, diverticulitis (outpouchings of the colon), and hernia. Diarrhea may be a sign of gastric cancer, colon cancer, rectal cancer, bowel cancer, and other cancers, and it also may occur on the growth or spread of these types of cancer.

Lactose intolerance and certain medications, such as antibiotics, can increase the risk of diarrhea. Anxiety about cancer or cancer treatment also can contribute to the development of diarrhea.

Etiology and the disease process: Chemotherapy and radiation therapy can cause changes in the function of the intestines, including increased or decreased peristalsis (the wavelike contraction of the muscles to propel the contents of the intestines through the digestive tract). An increase in peristalsis can cause stool to move faster through the intestines, leading to diarrhea or cramping. Chemotherapy also can change the normal bacteria in the intestines, causing diarrhea.

Dehydration is a concern for patients who have diarrhea. Dehydration occurs when more fluid is lost than is taken in, and the body does not have enough water and other fluids to carry out its normal functions. Signs of mild dehydration include dry mouth, weakness, dizziness, and fatigue. Signs of severe dehydration require immediate medical attention and include extreme thirst, irritability and confusion, very dry mouth, skin, and mucous membranes, decreased urination, low blood pressure, rapid heartbeat, and fever.

Incidence: Diarrhea is very common among patients undergoing cancer treatments, particularly those receiving certain chemotherapy drugs as well as radiation to the stomach or abdomen. Up to 60 percent of patients undergoing chemotherapy treatments experience diarrhea.

Symptoms: Symptoms of diarrhea include the passage of frequent loose or liquid stools more than three times in one day. Other symptoms that accompany diarrhea include urgency to have a bowel movement, bloating, and nausea.

Symptoms range from moderate to severe and vary among patients. Symptoms can impede cancer treatment, resulting in a delay, dose reduction, or discontinuation of therapy.

Changes in stool frequency, consistency, volume, or the presence of blood, mucus, or pus in the stool may indicate an underlying disease. If diarrhea occurs more than six times a day or does not resolve within twenty-four hours after taking prescribed antidiarrheal medications, the patient should call the prescribing physician.

Screening and diagnosis: A thorough review of the patient’s medical history and a physical exam are performed, and stool tests can be performed to identify blood and bacterial, fungal, parasitic, or viral pathogens. Diagnostic tests may include upper endoscopy, upper gastrointestinal series (barium swallow), abdominal X-rays, sigmoidoscopy, and colonoscopy.

Treatment and therapy: Symptom management is critical to avoid an interruption in the delivery of cancer treatment. A registered dietitian can provide nutritional therapy to help the patient develop an eating plan that meets dietary requirements while reducing side effects, helping to make treatment more tolerable. In some cases, antidiarrheal medications are prescribed. First-line treatment includes loperamide and diphenoxylate/atropine. Second-line treatment for persistent, chronic diarrhea includes octreotide subcutaneous injections. Steroids are often used in patients undergoing immunotherapy. Patients need to ask their physician first before self-treating diarrhea and related symptoms, as some over-the-counter remedies could interfere with cancer treatment.

Conservative techniques to manage diarrhea include the following:

• Increasing fluid intake to prevent dehydration
• Eating bland foods in small amounts
• Following a clear liquid diet of juices and broth until symptoms subside
• Avoiding spicy, high-fat, and sugary foods
• Eating small, frequent meals
• Eating slowly and chewing food completely before swallowing
• Taking medication with food unless advised otherwise
• Avoiding high-fiber foods and dairy products
• Avoiding caffeine and alcoholic beverages
• Including high-potassium foods, as advised by the doctor

In addition to these recommendations, relaxation techniques such as deep breathing and guided imagery may help. Patients should follow their physician’s specific guidelines for managing treatment side effects and should call the doctor when symptoms are severe or persist for more than twenty-four hours. When necessary, nutritional supplements also may be recommended to ensure sufficient caloric and nutrient intake. However, aloe, milk thistle, ginseng, coenzyme Q10, and vitamin C in large qualtities should be avoided.

Prognosis, prevention, and outcomes: Diarrhea can be effectively managed with conservative treatments and medications and is generally relieved when cancer treatments are completed. There usually are no long-term effects of gastrointestinal symptoms that are properly managed, according to the American Cancer Society.

Hospitalization is recommended for patients with severe dehydration or diarrhea that results in the inability to maintain adequate hydration or nutrition and for patients with chronic diarrhea that does not resolve within twenty-four hours after taking prescribed antidiarrheal medications.

Untreated, chronic diarrhea can cause significant morbidity and mortality because of nutritional deficiencies, and fluid and electrolyte imbalances may lead to potentially life-threatening dehydration or impaired kidney function.

Although cancer treatments can result in diarrhea that may be temporarily unpleasant to the patient, the potential side effects, if adequately managed under a physician’s care, should be measured against the cancer-fighting benefits of a particular treatment.

Bibliography

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"Gastrointestinal Complications." National Cancer Institute, 5 Jan. 2024, www.cancer.gov/about-cancer/treatment/side-effects/constipation/gi-complications-pdq. Accessed 20 June 2024.

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McQuade, Rachel M., et al. "Anti-Colorectal Cancer Chemotherapy-Induced Diarrhoea: Current Treatments and Side-Effects." International Journal of Clinical Medicine, vol. 5, no. 7, 2014, pp. 393–406. DOI:10.4236/ijcm.2014.57054.

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Yarbro, Connie Henke, et al. Cancer Symptom Management. 4th ed., Jones, 2014.