Association of CYP2C19 Polymorphisms with Survival of Breast Cancer Patients Using Tamoxifen: Results of a Metaanalysis

Background: Previous studies accessing the association of CYP2C19 with outcomes of patients using tamoxifenfor breast cancer have yielded conflicting results. The aim of this meta-analysis is to obtain a more precise estimateof effects of CYP2C19 polymorphisms and to clarify their effects on survival of the breast cancer patients usingtamoxifen. Materials and
Methods: A systematic search of PubMed and Embase was performed, comparingpatients with or without CYP2C19*2 and CYP2C19*17, relevant articles searched for. The following outcomeswere included from the eligible studies: disease-free survival (DFS) and overall survival (OS), expressed byhazard ratios (HR) with corresponding 95% confidence interval (CI). Subgroup analysis by genotypes was alsoperformed. Pooled estimates were calculated using random-effect model in accordance to the heterogeneity.
Results: Six studies met the inclusion criteria. The integrated OR on the association between CYP2C19 andDFS, calculated by the random-effect model, was 0.54 (95%CI=0.34-0.84, p=0.013). Subgroup analysis showedthat both CYP2C19*2 and CYP2C19*17 were associated with increased survival. The pooled results of twostudies for OS were OR=0.46 (95%CI=0.21-1.01, p=0.233).
Conclusions: This meta-analysis suggests that theCYP2C19*2 and CYP2C19*17 genotypes are associated with increased survival in breast cancer patients usingtamoxifen.