Assessment of small intestinal damage in patients treated with pelvic radiotherapy.

Pelvic radiotherapy almost always induces intestinal symptoms. We investigated the radiation-induced damage to the small intestinal mucosa and evaluated its relationship with symptoms, using cellobiose/mannitol permeability test (CE/MA) and plasma postheparin diamine oxidase test (PHD) in 20 patients treated with pelvic radiotherapy. The symptoms developed during radiotherapy were noted. Intestinal permeability significantly (p=0.013) increased from 0.021±0.026 to 0.047±0.055 (mean # SD) after 15 days of radiotherapy, while it returned to normal values (0.010#0.015) at the end of radiotherapy. PHD values did not change. All patients developed intestinal symptoms. These findings indicate that pelvic radiotherapy induces an early small bowel mucosa damage followed by mucosal adaptation. Acute intestinal symptoms during pelvic radiotherapy may not depend only on small intestinal mucosal damage.