Management of HER2-low metastatic breast cancer : a comprehensive statement by an expert group from the Middle East and Africa region

Abstract

Approximately 50 to 67% of breast cancers (BCs), traditionally categorized as human epidermal growth factor receptor 2 (HER2)-negative, but demonstrating low HER2 expression, are now being defined as a new HER2-low subset or HER2-low category of BC. For metastatic BC (mBC), standard therapy options include targeted approaches, such as cyclin-dependent kinase 4/6 inhibitors, phosphoinositide 3-kinase inhibitors, poly (adenosine diphosphate-ribose) polymerase inhibitors, and anti-programmed death-ligand 1 agents, depending on tumor type and its molecular profile. Recent clinical trials reported significant clinical benefits from novel anti‑HER2 antibody‑drug conjugates, such as trastuzumab deruxtecan in HER2‑low mBC. Novel treatment options have increased the complexity of the clinical decision‑making process, particularly for treatment sequencing for each clinical setting. A regional expert committee meeting was held to discuss the challenges, overcome limitations, and present recommendations to enhance HER2 reporting as well as treatment of patients with HER2‑low mBC in the Middle East and Africa region.