Efficacy of Synbiotics to Reduce Symptoms and Rectal Inflammatory Response in Acute Radiation Proctitis: A Randomized, Double-Blind, Placebo-Controlled Pilot Trial

Purpose: Evaluate whether the daily intake of synbiotics improves symptoms and rectal/systemic inflammatory response in patients with radiation-induced acute proctitis. Methods and Materials: Twenty patients who underwent three-dimensional conformal radiotherapy for prostate cancer were randomized to intake either a synbiotic powder containing Lactobacillus reuteri (10(8) CFU) and soluble fiber (4.3 g) or placebo. EORTC QLQ-PRT23 questionnaire was applied before the beginning of radiotherapy and after the fifth, sixth, and seventh weeks of treatment, and the sum of both the complete (proctitis symptoms plus quality of life) and partial (proctitis symptoms) scores were compared. Fecal calprotectin was measured at Day 0 and in the fourth week of treatment, and serum C-reactive protein/albumin ratio were measured in the fourth week of treatment. Results: Both the complete and partial questionnaire score (median and range) were higher in the fifth and sixth weeks in the placebo group; there was a higher increase in fecal calprotectin in the placebo group and no difference comparing CRP/albumin ratio. Conclusions: Synbiotics reduce proctitis symptoms and improve quality of life by preventing rectal inflammation during radiotherapy for prostate cancer.