Effect of pelvic irradiation on gastrointestinal function: A prospective longitudinal study

Abstract

purpose: Although radiation enteritis is a well-recognized sequel of therapeutic irradiation, the effects of abdominal and/or pelvic irradiation on gastrointestinal function are poorly defined and treatment is often unsuccessful. To determine both the short- and long-term effects of therapeutic irradiation on gastrointestinal function, we performed a prospective study. patients and methods: Various aspects of gastrointestinal function were evaluated in 27 patients with potentially curable malignant disease (23 female, 4 male) before the commencement of, during, and 6 to 8 weeks, 12 to 16 weeks, and 1 to 2 years following completion of radiation therapy. Seventeen patients received pelvic irradiation alone and 10 patients received both abdominal and pelvic irradiation. Gastrointestinal symptoms, absorption of bile acid, vitamin B 12, lactose, and fat, gastric emptying, small-intestinal and whole-gut transit, stool weight, and intestinal permeability were measured. Results were compared with those obtained in 18 normal volunteers. results: All 27 patients completed at least 2 series of measurements and 18 patients completed all 5 series of experiments. During radiation treatment, increased stool frequency (p <0.001) was associated with decreased bile acid and vitamin B 12 absorption (p <0.001 for both), increased fecal fat excretion (p <0.05), an increased prevalence of lactose malabsorption (p <0.01), and more rapid small-intestinal (p <0.01) and wholegut (p <0.05) transit. Although there was improvement in most of these changes with time, at 1 to 2 years after the completion of irradiation, the frequency of bowel actions was greater (p <0.001), bile acid absorption was less (p <0.05), and small-intestinal transit was more rapid (p <0.01) when compared with that of baseline and the normal subjects. At this time, at least 1 parameter of gastrointestinal function was abnormal in 16 of the 18 patients. Stool weight was greater (p <0.05) and whole-gut transit faster (p <0.01) in patients who received both pelvic and abdominal irradiation, when compared with those who received pelvic irradiation alone. Stool frequency (p <0.001) and fecal fat excretion (p <0.05) were greater in those patients who had surgery before radiation therapy. conclusion: Pelvic irradiation is usually associated with widespread, persistent effects on gastrointestinal function.