Adjuvant Endocrine Therapy in Postmenopausal Women: Making Treatment Choices Based on the Magnitude of Benefit

Hormone-receptor positive, HER2 negative breast cancers account for the vast majority of early stage breast cancers, particularly in postmenopausal women. Adjuvant endocrine therapy is an essential component of multimodality therapy for such cancers, lowering the risk of local-regional and of metastatic recurrence, improving overall survival, and enabling "less" in the way of breast or axillary surgery and radiation therapy for many women. In the past decade, advances in adjuvant endocrine therapy in postmenopausal women include widespread use of aromatase inhibitors instead of or in sequence with tamoxifen, and use of extended durations of endocrine treatment beyond the classical "5 years" of recommended therapy. However, the judicious use of these treatments to optimize outcomes depends on considering features of the tumor stage and biology and careful attention to and management of symptoms related to these treatments.