Alcohol drinking and epithelial ovarian cancer risk. A systematic review and meta-analysis

Objective: In order to provide an updated quantification of the association between alcohol drinking and epithelial ovarian cancer risk, we conducted a meta-analysis of published observational studies. Methods: Using PubMed, we performed a literature search of all case-control and cohort studies published as original articles in English up to September 2011. We included 27 observational studies, of which 23 were case-control studies, 3 cohort studies and one pooled analysis of prospective cohort studies, including a total of 16,554 epithelial ovarian cancer cases. We derived pooled meta-analytic estimates using random-effects models. Results: The pooled relative risk (RR) for any alcohol drinking compared with non/occasional drinking was 1.00 [95% confidence interval (CI), 0.95-1.05]. The RRs were 0.97 (95% CI, 0.92-1.02), 1.03 (95% CI, 0.96-1.11) and 1.09 (95% CI, 0.80-1.50) for light (≤ 1 drink/day), moderate (> 1 to < 3 drinks) and heavy drinking (≥ 3 drinks/day), respectively. In particular, the pooled RR for invasive epithelial ovarian cancers was 1.00 (95% CI, 0.95-1.06), while for borderline cancers was 0.96 (95% CI, 0.74-1.26). Stratified analyses across cancer histotypes revealed a modest protective effect of alcohol on endometrioid epithelial ovarian tumors (RR = 0.82, 95% CI, 0.70-0.96), while no association was found for serous (RR = 1.00, 95% CI, 0.84-1.19), mucinous (RR = 0.91, 95% CI, 0.78-1.08) and clear cell (RR = 0.93, 95% CI, 0.76-1.14) cancers. There was no evidence of publication bias. Conclusions: This comprehensive meta-analysis provided no evidence of a material association between alcohol drinking and epithelial ovarian cancer risk.