The significance of probiotics in preventing radiotherapy-induced diarrhea in patients with cervical cancer: A systematic review and meta-analysis

A systematic review and meta-analysis was designed to evaluate the efficacy and safety of probiotics for prevention of radiotherapy-induced diarrhea (RID) in patients with cervical cancer. Previous studies failed to give a comprehensive analysis of the efficacy and safety of probiotics in this point. We searched the Cochrane Library, PubMed, EMBASE and Web of Science up to June 4, 2018. We also hand searched some studies included in previous reviews. Our primary outcome aims to compare the incidence of all Common Toxicity Criteria (CTC) grades of RID and adverse events (AEs) in both probiotics groups and placebo groups. Relative risk (RR) with its 95% confidence interval (CI) was used to compare the efficacy of probiotics in prevention of RID, and the pooled RRs were estimated using a fixed- or random-effect model; heterogeneity was assessed with Cochran's Q and Higgins I2 test. Two reviewers assessed trial quality and extracted data independently. The analysis and bias for each of included studies were performed and assessed using Review Manager 5.2. Nine randomized, placebo-controlled studies (N = 1508 participants) were included for assessing the efficacy of probiotics. Compared with placebo groups, participants in probiotic groups experienced much lower incidence of RID with RR of 0.61 (95% CI 0.46–0.81; P = 0.0007). In addition, significant results were also observed in CTC grade ≥2 and grade ≥3 RID, with the pooled RRs of 0.52 (95% CI 0.30–0.98; P = 0.02) and 0.32 (95% CI 0.12–0.82; P = 0.02) respectively. Eight studies, included 1410 participants (726 consuming probiotics, 657 consuming placebo, 27 lost to follow-up), were used for the analysis of safety of probiotics. Of the 8 studies, 4 studies had no AEs caused by probiotics, while another 4 studies reported varying degrees of AEs during their treatment. Probiotics may have a beneficial effect in prevention of RID generally, especially for Grade ≥2 or 3 diarrhea. Probiotics may be safe and rarely cause severe AEs during treatment.