Radiation Enteritis/ Proctitis

1. Radiation Enteritis/ Proctitis RaneenOmary

2. Contents • Definition • Pathogenesis • Epidemiology • Acute Radiation Enteritis • Chronic Radiation Enteritis • Risk Factors • Diagnosis • DD • Medical Management • Surgery • Prognosis

3. Definition • Radiation Enteritis/Proctitis Functional disorder of the small and large intestines secondary to abdominal/ pelvic radiation * Both radiation enteritis and proctitis have acute and chronic manifestations

4. Pathogenesis • Cells with a high proliferative rate, such as the gastrointestinal epithelium, are susceptible to injury from radiation • The primary effect of radiation is on mucosal stem cells within the crypts of Lieberkuhn • Inflammation, edema, shortening of villi (small absorption area) • Histological changes within hours • Inflammation, abbcess- 2-4 weeks. • ulcers

5. ** Subsequent Changes: • Vasculitis • Fibrosis (submucosa) • Thickening of the small intestine (ischemia, lymphatic damage) • Also: ulceration perforation, fistula, abcess./Fibrosis, stricture, obstruction • Absorption of fats, carbohydrates, protein, bile salts, B12 vitamin. • Lactose (bacterial overgrowth?)

6. Epidemiology • Almost every patient undergoing RT to the abdomen or pelvis will show signs of acute enteritis • Only 5% to 15% of patients treated with abdominal/pelvic RT will develop chronic enteritis • No sex, age, or race correlation

7. Acute Radiation Enteritis • Occurs as a result of the direct effects of radiation on the bowel mucosa • Symptoms include:  diarrhea, abdominal pain, nausea and vomiting, anorexia, and malaise • Acute pathologic effects resolve and typically disappear two to six weeks after the completion of RT • Patients who develop acute intestinal toxicity are at increased risk for chronic effects

8. Chronic Radiation Enteritis • Late radiation effects typically are manifested 8 to 12 months after RT, although toxicity may not appear until years later in some cases • Symptoms include:  diarrhea, nausea, weight loss, abdominal pain.. • intestinal obstruction, perforation, malabsorption, lactose intolerance • Chronic radiation enteritis is due to an obliterativearteritis that leads to intestinal ischemia, which can result in stricture, ulceration, fibrosis and occasionally fistula formation

9. Risk Factors • Dose of radiation, and duration • Volume of normal bowel treated • Concomitant chemotherapy • Individual patient variables

10. Diagnosis • History of prior radiation exposure • Upper Gastointestinal Series • Enteroclysis • CT • Enteroscopy • Capsule Endoscopy • Colonoscopy

11. Capsule endoscopy showing a jejunal stricture secondary to radiation enteritis. Abnormal jejunalvilli secondary to radiation enteritis as seen during capsule endoscopy.

12. DIFFERENTIAL DIAGNOSIS • Post-surgical adhesions • Abdominal metastases • Lymphoma • Crohn's disease • Infections • Ischemic or ulcerative colitis • Intestinal pseudo-obstruction

13. Medical Management • Prevention is the key to avoiding chronic radiation enteritis

14. * Once established, treatment should be as conservative as possible focusing on relief of symptoms • Dietary Recommendations – avoiding high fiber diet, lactose. • Anti-diarrheal Agents-loperamide • Antibiotics • 5-ASA Drugs -sulfasalazine

15. Surgery •  Surgery for radiation enteritis should be avoided if possible because of several inherent difficulties in operating on patients with chronic radiation injury • Approximately 1/3 of patients progress to the point where surgery is required • The most common indications for surgery have been persistent ileus, intestinal fistulization, and massive adhesions • Surgical mortality rates are as high as 10 to 22 percent and many patients require more than one laparotomy

16. Prognosis • Variable • Early mortality is usually due to cancer recurrence • 5-year survival is approximately 70% in those without cancer recurrence, although many patients continue to have troubling digestive symptoms