SummaryThe three top abstracts at the 2020 virtual San Antonio Breast Cancer Symposium regarding hormone-receptor-positive early breast cancer, from our point of view, were the long-awaited results from PenelopeB and RxPONDER as well as the data from the ADAPT trial of the West German Study Group. PenelopeB failed to show any benefit by adjuvant palbociclib when added to standard endocrine therapy in patients without pathologic complete response after neoadjuvant chemotherapy. RxPONDER demonstrated that postmenopausal patients with early hormone receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2−) breast cancer, 1–3 positive lymph nodes and an Oncotype DX Recurrence Score of less than 26 can safely be treated with endocrine therapy alone. In contrast, in premenopausal women with positive nodes, adjuvant chemotherapy plays still a role even in case of low genomic risk. Whether the benefit by chemotherapy is mainly an indirect endocrine effect and if ovarian function suppression would be similarly effective, is still a matter of debate. The HR+/HER2− part of the ADAPT umbrella trial investigated the role of a Ki-67 response to a short endocrine therapy before surgery in addition to Oncotype DX—performed on the pretreatment biopsy—to identify low-risk patients who can safely forgo adjuvant chemotherapy irrespective of menopausal status.
180TiP Palbociclib, trastuzumab and endocrine therapy (ET) versus treatment of physician's choice (TPC) in metastatic HER2-positive and hormone receptor-positive (HER2+/HR+) breast cancer (BC) with PAM50 luminal intrinsic subtype (SOLTI-1303 PATRICIA II): A randomized phase II trial
