Radiation Enteritis is damage to the bowel that occurs during or after radiation treatment for cancer.  Radiation enteritis can be acute, occurring during the course of treatment or chronic, occurring after the course of treatment.  Radiation causes damage to cancer cells and prevents them from dividing.  This is how the therapy treats the cancer.  In the process, healthy cells are also damaged, hopefully to a smaller extent than the cancer cells.  Symptoms of radiation enteritis include abdominal pain, nausea, vomiting, diarrhea and rectal bleeding.  Risk factors for radiation enteritis include;

• Advanced patient age
• Prior abdominal surgery leading to intraperitoneal adhesions (Adhesions fix portions of the small or large intestine in the radiated field.)
• History of pelvic inflammatory disease
• Hypertension
• Diabetes mellitus
• Thin physique
• Administration of chemotherapy
• Other risk factors (eg, collagen vascular diseases, xeroderma pigmentosum, Cockayne syndrome)

Other risk factors include total radiation dose and whether it was given at one time or divided up over weeks.  Shielding of other organs and the bowel from radiation may reduce the incidence of this problem.

Radiation enteritis is diagnosed by history and then by performing a colonoscopy to visualize the damage.  CT scans with contrast and barium studies may reveal obstruction of the bowel, and other forms of damage.  Radiation damage is scored on a scale of zero (minimal or none) to five (severe).  Occasionally, you can swallow a small pill that has a camera inside of it to take pictures of your intestines as it travels through your GI tract to see the extent of the damage and its location.  Treatment is symptomatic and includes antacids, anti-diarrheals and narcotics.  Sulfasalazine has been proven to reduce radiation injury to the bowel. Amifostine is another medication, given intravenously, that can treat radiation damage to the prostate. Surgical intervention is reserved for the most severe cases and to treat obstruction, perforation, fistulas and bleeding.