Commentary (Kaklamani/Gradishar): Adjuvant Hormonal Therapy in Early Breast Cancer

The use of adjuvant endocrine therapy in early-stage breast cancer is thought to eradicate micrometastatic disease that may lead to systemic recurrences. Until relatively recently, the standard adjuvant endocrine therapy option was tamoxifen. Data from the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) overview analysis reported a 50% reduction in the risk of relapse and a 28% reduction in the risk of death in estrogen receptor (ER)- positive patients treated with 5 years of tamoxifen.[1] This benefit was observed regardless of menopausal or lymph node status and whether or not patients were receiving chemotherapy. There was no such benefit documented in ER-negative cancers receiving tamoxifen. Tamoxifen has also been associated with a 47% reduction in the risk of developing contralateral breast cancer.[1]