Background & aims: A meta-analysis to estimate the efficacy of probiotics in prevention of radiation-induced bowel disease after pelvic radiotherapy has been performed. Previous attempts have arguably failed to provide a comprehensive analysis of clinical trials and their outcomes.
Methods: We searched for studies indexed in Medline, EMBASE, Cochrane Library, and on-line clinical trials registers. There was no language or time limit. Each study was evaluated for methodological quality and outcomes. We identified four outcomes on which to perform meta-analysis: incidence of diarrhoea, loperamide use, watery, and soft stools (Bristol Stool Chart). Odds ratio (OR) was used to compare efficacy, and the pooled OR was estimated using a random effects model; heterogeneity was assessed with Cochran's Q and Higgins I(2) test. Analyses were performed using Review Manager 5.2.
Results: Ten studies were included in our systematic review, of which six were subjected to meta-analysis to compare probiotics against placebo. Quality assessment showed an unclear risk due to incomplete outcome data and lack of performance of intention-to-treat analysis, while blinding and randomization issues were present in certain studies. Pooled results showed heterogeneity (Cochran's Q: p < 0.05; I(2): high). However the pooled OR for the incidence of diarrhoea, synthesized from 6 studies, significantly favoured the use of probiotics over control (OR = 0.44, 95% CI 0.21-0.92). Numerically, but not statistically, probiotics seem to decrease loperamide use (OR = 0.29, 95% CI 0.01-6.80) and the incidence of watery stools (OR = 0.36, 95% CI 0.05-2.81).
Conclusions: In conclusion, probiotic supplementation shows a probable beneficial effect in the prevention, and possible benefit in the treatment, of radiation-induced diarrhoea.
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