Just in are the results of the SWOG S1007 RxPONDER trial, which evaluated the benefit of chemotherapy in women with early-stage hormone receptor–positive, HER2-negative breast cancer and node-positive disease.¹ The data showed that many postmenopausal women can skip adjuvant chemotherapy, based on a 46% reduction in the risk of invasive disease–free survival events at 5 years. However, premenopausal women may still derive a benefit from adjuvant chemotherapy. Kevin Kalinsky, MD, MS, Director of the Glenn Family Breast Center at Winship Cancer Institute of Emory University, Atlanta, presented these findings at the 2020 San Antonio Breast Cancer Symposium.¹

The number of circulating tumor cells (CTCs) assessed at baseline and at about 1 month after cancer-directed treatment was strongly associated with overall survival in patients with metastatic breast cancer, according to a large retrospective pooled analysis reported at the 2020 San Antonio Breast Cancer Symposium (SABCS).¹ Monitoring early treatment responses using CTCs was predictive for overall survival in all tumor subtypes: luminal-like, HER2-positive, and triple-negative breast cancer.

On December 16, the U.S. Food and Drug Administration (FDA) approved margetuximab-cmkb (Margenza) in combination with chemotherapy for the treatment of adult patients with metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 regimens, at least one of which was for metastatic disease.

In a study presented at the 2020 San Antonio Breast Cancer Symposium and concurrently published in the Journal of Clinical Oncology, Joseph A. Sparano, MD, and colleagues described the development and validation of a new prognostic tool. RSClin integrates the 21-gene recurrence score and clinical-pathologic factors to allow for the creation of individualized estimates of risk for distant disease recurrence and prediction of risk-reduction benefit of adjuvant chemotherapy in patients with early breast cancer.

Extended follow-up results from the phase III monarchE trial showed that adding the cyclin-dependent kinase inhibitor abemaciclib to standard adjuvant endocrine therapy continued to improve invasive disease­–free survival in patients with high-risk, node-positive, early-stage, hormone receptor (HR)-positive, HER2-negative breast cancer. Compared with patients who received endocrine therapy alone, patients who also received abemaciclib had a 28.7% reduced risk of invasive disease. The study was presented by Joyce A. O’Shaughnessy, MD, and colleagues at the 2020 San Antonio Breast Cancer Symposium.