Meta-analysis of pre-operative aromatase inhibitor versus tamoxifen in postmenopausal woman with hormone receptor-positive breast cancer

Purpose Clinical trials have reported conflicting results as to whether pre-operative aromatase inhibitors (AIs) improve outcome over pre-operative tamoxifen in postmenopausal women with hormone receptor-positive breast cancer. Methods We performed a meta-analysis comparing primary and secondary end points of pre-operative AI and pre-operative tamoxifen. The event-based risk ratio (RR) with 95% confidence intervals (95% Cis) were derived, and a test of heterogeneity was applied. Results Four studies (1,160 patients) met the inclusion criteria for the analysis. Meta-analysis showed that pre-operative AI was more effective than pre-operative tamoxifen. Pooled results of clinical efficacy were as follows: clinical objective response rate (RR, 1.29; 95% CI, 1.14-1.47; P < 0.001), ultrasound objective response rate (RR, 1.29; 95% CI, 1.10-1.51; P = 0.002), and breast conserving surgery (BCS) rate (RR, 1.36; 95% CI, 1.16-1.59; P < 0.001). Hot flashes, nausea, and fatigue were not different between the pre-operative AI and pre-operative tamoxifen groups. Although headache was more frequent in the pre-operative AI group (P = 0.011), it was a manageable toxicity and was not clinically relevant. Conclusion Pre-operative AI has better BCS rate than tamoxifen and in terms of toxicities, is not inferior to tamoxifen; therefore, we could suggest pre-operative AI instead of tamoxifen for those postmenopausal patients with hormone receptor positive breast cancer, not eligible for chemotherapy.