Enteritis and cancer

ALSO KNOWN AS: Radiation enteritis

RELATED CONDITIONS: Crohn disease's, irritable bowel syndrome

DEFINITION: Enteritis is an inflammation of the small or large intestine or both. Enteritis can be acute (short-term) or chronic (long-lasting).

Risk factors: In cancer patients, enteritis is caused by radiation therapy to the abdomen, pelvic area, or rectum. Radiation therapy is given either to treat an inoperable tumor or as an adjunct to surgery or chemotherapy. The likelihood of developing radiation enteritis depends on multiple factors, including:

• where the radiation was targeted
• strength and frequency of radiation treatment
• tumor size
• amount of bowel (large or small intestine) exposed to radiation
• whether radiation therapy was given at the same time as chemotherapy
• presence of radioactive implants to target tumors
• patient health and nutritional status

Generally, the higher the dose and frequency of radiation and the larger the amount of intestine exposed, the more likely the individual is to develop radiation enteritis. Patients who have diabetes, high blood pressure, poor nutritional status, or conditions that interfere with blood flow to the intestines are more likely to develop radiation enteritis.

Etiology and the disease process: Enteritis is an inflammation of the bowel. In noncancer patients, acute enteritis most often occurs because the individual has consumed food or water contaminated with bacteria or viruses that irritate the intestine. Chronic enteritis occurs from gastrointestinal disorders such as Crohn's disease. Radiation enteritis is a specific type of enteritis that occurs as a result of radiation therapy during cancer treatment.

Radiation is used to kill rapidly dividing cancer cells. However, it also kills normal cells, especially those that divide frequently. The cells lining both the large and small intestine tend to divide often and can be substantially damaged by exposure to radiation necessary to treat cancer occurring in the abdomen and pelvis.

As the cells lining the wall of the intestine are damaged, the digestive function is disrupted, and water and nutrients are no longer efficiently absorbed. In acute radiation enteritis, the changes to the cells are reversible, and the condition usually clears up a month or two after radiation therapy stops. In chronic radiation enteritis, the cellular damage continues. Symptoms usually improve for a time, but they recur between six and eighteen months after radiation therapy has been completed. Damage to the intestinal lining in chronic radiation enteritis is permanent, and symptoms are difficult to control.

Incidence: There is controversy over how many people develop radiation enteritis. Some studies have found that almost all patients exposed to abdominal radiation develop some acute symptoms, while other studies have recorded rates of about 50 percent. The Cleveland Clinic puts the number between 5 and 15 percent. This variation is probably due to different techniques and doses used at different cancer centers. Of those people who develop acute symptoms, between 2 and 20 percent develop chronic problems.

Symptoms: Many symptoms of acute and chronic radiation enteritis are similar. They include crampy abdominal pain, nausea, vomiting, watery or bloody diarrhea, mucous discharge, and bleeding from the rectum. Individuals with chronic enteritis also lose weight, have vitamin deficiencies, and pass loose, fatty, or greasy stools. Occasionally, with chronic enteritis, the intestine may become obstructed or a perforation (hole) may develop.

Screening and diagnosis: For acute radiation enteritis, diagnosis is made based on symptoms appearing shortly after radiation therapy has begun. Symptoms may take between nine and fourteen months to appear. For chronic radiation enteritis, the observation of symptoms and a patient history are used to make a diagnosis. In chronic enteritis, tests are done to rule out a return of the tumor or other conditions that could cause similar symptoms.

Treatment and therapy: Radiation enteritis is treated by managing the symptoms. Dietary changes include avoiding spicy, fatty, and high-fiber foods, alcohol, and milk products because the intestine often loses the ability to make the enzyme lactase, which is needed to digest milk. Diarrhea is treated with antidiarrheal medicines such as bismuth subsalicylate (Kaopectate), diphenoxylate and atropine (Lomotil), anhydrous morphine (Paregoric), or loperamide (Imodium). Fluid intake is increased to compensate for fluids lost with diarrhea. Antispasmodics may also be given to slow contractions in the bowel. Nutritional counseling is important, especially in chronic enteritis, because the bowel loses the ability to absorb nutrients. Nutritional supplements and digestive aids are often given. Surgery to remove the damaged portion of the bowel in chronic enteritis is controversial due to high postoperative morbidity rates. In the mid-2020s, new treatments emerged for acute and chronic enteritis, including probiotics and fecal transplant. Amino acid-based oral rehydration solution can also reverse damage to the intestines.

Prognosis, prevention, and outcomes: Symptoms of acute radiation enteritis usually continue two to three weeks after radiation therapy has finished. Within two to three months, symptoms usually disappear completely, and the cells lining the intestine return to normal. However, in some cases, symptoms may be delayed and appear months afterward. In chronic radiation enteritis, the cells lining the intestinal wall are permanently damaged, and symptoms continue indefinitely, although treatment may help to control them. Nutritional counseling and a modified diet can help reduce some symptoms of the disorder.

Bibliography

Bhutta, Beenish. “Radiation Enteritis - StatPearls.” NCBI, 17 Aug. 2023, www.ncbi.nlm.nih.gov/books/NBK526032. Accessed 19 June 2024.

Dodd, Marilyn J. Managing the Side Effects of Chemotherapy and Radiation. New ed. San Francisco: UCSF Nursing P, 2001.

Harb, A. H., C. Abou Fadel, and A. I. Sharara. "Radiation Enteritis." Current Gastroenterology Reports, vol. 16.5, 2014.

Keane, Maureen, and Daniella Chace. What to Eat if You Have Cancer: Healing Foods That Boost Your Immune System. Updated 2d ed. New York: McGraw, 2007.

Lackner, K., K. B. Krug. Avoiding Errors in Radiology: Case-Based Analysis of Causes and Preventive Strategies. Stuttgart: Thieme, 2011.

Pal, Neelu. “Radiation Enteritis and Proctitis.” Medscape, 6 Oct. 2023, emedicine.medscape.com/article/197483-overview?form=fpf. Accessed 19 June 2024.

“Radiation Enteritis.” MedlinePlus, 4 May 2022, medlineplus.gov/ency/article/000300.htm. Accessed 19 June 2024.

“Radiation Enteritis: Treatment & Management.” Cleveland Clinic, 25 Apr. 2022, my.clevelandclinic.org/health/diseases/22846-radiation-enteritis. Accessed 19 June 2024.

Ren, Huiwen, et al. "Research Progress and Treatment of Radiation Enteritis and Gut Microbiota." Radiation Oncology Journal, vol. 41, no. 2, 2023, pp. 61-68, doi.org/10.3857/roj.2023.00346. Accessed 19 June 2024.

Smith, Tom. Coping with Bowel Cancer. London: Sheldon, 2005.

Staritz, M., et al., eds. Side Effects of Cancer Chemotherapy on the Gastrointestinal Tract. Boston: Kluwer Academic, 2003.