Effects of a Laxation and Probiotic Bowel Preparation Regimen: A Randomized Controlled Trial in Patients Undergoing...

Aim: To determine the effect of bulking and osmotic laxation regimens on reducing rectal gas in patients receiving external beam radiation therapy for prostate cancer.Methods: A single blinded randomized controlled trial was conducted. Participants assigned to the intervention group (IG) were instructed to consume a bulking laxative and probiotic and the standard care group (SC) instructed to consume an osmotic laxative. Both groups followed a standard low gas diet. Rectal gas ratings were determined from cone-beam computed tomography (CBCT) scans. Dietary and laxative compliance, bowel habits, fiber and fluid intakes were determined from food diaries.Results: Demographic characteristics were not significantly different between the two treatment arms. The mean age was 74 years. Participants were randomized into the IG (n = 8) and SC group (n = 9). Analysis of 433 CBCT scans indicate the odds of a higher rectal gas rating were significantly increased for the IG compared with the SC group (OR 3.2, 95% CI 1.77-5.78, P < 0.001).Conclusions: The osmotic laxative was more effective at achieving lower rectal gas levels than a bulking laxative with probiotic in this study. Larger studies of commonly used laxatives are required to develop recommendations for bowel preparation during radiotherapy to the prostate.