Lost in Translation? Estrogen Receptor Status and Endocrine Responsiveness in Breast Cancer

Abstract

this editorial and elsewhere 2-4,12,14 testify to the long arc of hormone receptor‐positive breast cancer, confirm the enduring overall safety of tamoxifen and AIs, and provide reassurance that the well-characterized major adverse events of therapy either stabilize or resolve with cessation of treatment. The substantial near-term successes of adjuvant chemotherapy and endocrine therapy have shifted both the natural history and the dialogue in ER-positive, early-stage breast cancer for oncologists and patients alike. The issue of late recurrence—deep time for clinicians and survivors— has emerged as a fundamental challenge. RCTs have shown equivalence for either 5 years of AI treatment or a sequenced regimen of tamoxifen followed by an AI for a total of 5 years. 13,18 For women who receive AI-based adjuvant treatment, it remains unclear whether a longer program of extended therapy with an AI beyond 5 years of initial adjuvant treatment will outperform a shorter 5-year course of adjuvant endocrine therapy. Progress in the deep time problem of early-stage breast cancer will depend on answering the long and the short of that question.