Raneen Omary

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

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

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

** 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?)

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

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

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 obliterative arteritis that leads to intestinal ischemia, which can result in stricture, ulceration, fibrosis and occasionally fistula formation

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

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

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

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

Medical Management Prevention is the key to avoiding chronic radiation enteritis

* 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

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

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