Toxicity of Adjuvant Endocrine Therapy in Postmenopausal Breast Cancer Patients: A Systematic Review and Meta-analysis

Aromatase inhibitors are associated with consistent improvements in disease-free survival but not in overall survival. We conducted a literature-based meta-analysis of randomized trials to examine whether the relative toxicity of aromatase inhibitors compared with tamoxifen may explain this finding.

We conducted a systematic review to identify randomized controlled trials that compared aromatase inhibitors and tamoxifen as primary adjuvant endocrine therapy in postmenopausal women by searching MEDLINE, EMBASE, and databases of the American Society of Clinical Oncology and San Antonio Breast Cancer Symposium. Odds ratios (ORs), 95% confidence intervals (CIs), absolute risks, and the number needed to harm associated with one adverse event were computed for prespecified serious adverse events including cardiovascular disease, cerebrovascular disease, bone fractures, thromboembolic events, endometrial carcinoma and other second cancers not including new breast cancer. All statistical tests were two-sided.