Pathophysiology and therapy of chronic radiation-induced injury to the colon.

Radiotherapy of pelvic malignancies causes chronic radiation damage to the gut in approximately 5% of patients. The injury can lead to local ischemia and fibrosis with the development of ulcers, strictures and lower gastrointestinal bleeding. The clinical presentation varies from mild disease to debilitating rectal bleeding, diarrhea, obstruction and fistula formation. Therapy should be directed toward the dominant symptom. Formalin instillation and endoscopic obliterative therapy can be used for bleeding due to telangiectasis. Nutritional intervention, e.g. total parenteral nutrition or elemental diets, is useful as adjunctive therapy to maintain hydration and nutritional status. Surgery should be reserved for severe refractory bleeding, fistulas or obstruction. Due to the recurrent character of the disease and the high complication rate, surgery should be viewed as an effort of last resort.