ASCO 2022 featured a couple of breast cancer-related presentations with the potential to shake up the clinical practice. First and foremost, results of the DESTINY-Breast 04 study demonstrated a significant progression-free (PFS) and overall survival (OS) benefit with trastuzumab deruxtecan in the treatment of HER2-low metastatic breast cancer (mBC) patients who received 1–2 prior lines of therapy. By effectively creating a new category of breast cancer, this trial will redefine the classical breast cancer classification and will significantly expand the population of patients who can benefit from HER2-targeted therapy. In TROpICS-02, sacituzumab govitecan, an antibody-drug conjugate directed against TROP-2, was found to delay the disease progression of patients with heavily pre-treated HR+/HER2- advanced breast cancer. Also in HR+/HER2- advanced breast cancer, the MAINTAIN study demonstrated a significant PFS benefit with the continued use of a CDK4/6 inhibitor with a switch in endocrine therapy partner in women who progressed while being treated with a CDK4/6 inhibitor. Finally, ASCO 2022 also showed that the significant PFS benefit obtained from adding the CDK4/6 inhibitor palbociclib to letrozole in the first-line treatment of postmenopausal women with HR+ advanced breast cancer did not translate into a significant OS benefit.

(Belg J Med Oncol 2022;16(5):251–6)