Pathophysiology and Therapy of Chronic Radiation-Induced Injury to the Colon

Abstract

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.

Rectal bleeding and its management after irradiation for uterine cervical cancer

“…Only one required transfusion 24 months after treatment completion. The treatment was safe and effective for patients with mild to moderate bleeding due to radiation proctitis, as reported by others (45,46). Viggiano et al (47) at the Mayo Clinic reported their experience of endoscopic neodymium:yttrium-argon-garnet laser coagulation of bleeding due to radiation.…”

Use of probiotics for prevention of radiation-induced diarrhea

“…This is the main mechanism underlying the pathophysiology of acute radiation-induced enteritis and colitis, which are a common and potentially severe complication among cancer patients treated with radiation therapy. Attempts to treat this complication with antibiotics, sucralfate, antiinflammatory drugs such as mesalazine and balsalazide, glutamine, octreotide, proteolytic enzymes, and hyperbaric oxygen have so far provided inconclusive clinical results with failure of treatment occurring in a substantial proportion of patients [1][2][3][4][5][6][7][8][9] . Furthermore, prophylactic use of sucralfate does not reduce the burden of radiationinduced bowel toxicity but rather, is associated with more severe gastrointestinal symptoms including bleeding and fecal incontinence [10,11] .…”

Late Toxicity and Quality of Life

“…Due to the forming of small collateral vessels, longer-term changes are manifested in the development of teleangiectasis and neovascularization. These superficial small vessels are fragile and therefore susceptible for trauma and subsequent mucosal bleeding (Donner 1998). Moreover, the lamina propria can become fibrotic, and collagen can be deposited under the superficial epithelium.…”