Redrawing the Lines: The Next Generation of Treatment in Metastatic Breast Cancer

Although not considered curative in nature, new therapeutic advances in metastatic breast cancer (MBC) have substantially improved patient outcomes. This article discusses the state-of-the-art and emerging therapeutic options for management of MBC. BC systemic therapy targets multiple key pathways, including estrogen receptor signaling, HER2 signaling, and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling. Other therapeutic strategies include targeting DNA repair, inhibiting immune checkpoints, and developing antibody-drug conjugates. Although surgery historically was reserved for palliation of symptomatic, large, or ulcerating masses, some data suggest a possibly expanding role for more aggressive locoregional therapy in combination with systemic therapy. As technology develops, biomarker-specific, line-agnostic, and receptor-agnostic treatment strategies will redraw the current lines of MBC care. However, tumor heterogeneity remains a challenge. To effectively reshape our approach to MBC, careful consideration of the patient perspective, the costs and value of novel treatments, and accessibility (especially in developing countries) is paramount.