Effects of hormone replacement therapy on the rate of recurrence in endometrial cancer survivors: A meta-analysis

Background: To quantify the effect of hormone replacement therapy (HRT) on the recurrence in endometrial cancer (EC) survivors through a meta-analysis. Methods: A systematic literature review was conducted through October 2013 and included studies reporting estimates of effect size for the relationship between HRT use and the risk of EC recurrence. Study design features that may affect the selection of participants, the detection of EC recurrence and manuscript publication were assessed. If there was no significant statistical heterogeneity across studies, then a fixed effects model was used to obtain pooled estimates for the effect of HRT use on EC recurrence by combining study-specific estimates of the odds ratio (OR). Results: One randomised trial and five observational studies included 896 EC survivors who used HRT and 1079 non-users. Over the combined study period, 19 of the 896 HRT users experienced recurrence, whereas 64 of the 1079 controls did. The meta-analysis based on the fixed effects model indicates no significant increase in the risk of recurrence in EC survivors using HRT relative to the control group (OR: 0.53; 95% confidence interval: 0.30-0.96, r(2) = 49.0). This pattern was also observed in the subgroup analysis for the stage and type of HRT. There was no evidence of any publication bias. Conclusions: Although based mainly on observational studies, the literature does not provide support for a positive relationship between HRT use and the risk of EC recurrence. Future research should verify this relationship through randomised controlled trials over a longer term. (C) 2014 Elsevier Ltd. All rights reserved.