Novel Treatment Approaches for Triple-Negative Breast Cancer

Triple-negative breast cancers share an aggressive biology, marked by increased recurrence risk and poorer survival compared with hormone receptor—positive subtypes. Few therapeutic trials have specifically focused on triple-negative breast cancer, and the treatment of patients with early-stage triple-negative breast cancer has changed little in the past decade. Over this time, however, attention has shifted to treatment approaches based on molecular subtypes of breast cancer, and investigation into the mechanistic underpinnings of these distinct subtypes has exploded. Converging preclinical rationales combined with early provocative clinical efficacy has focused recent attention on strategies targeting DNA repair defects for the treatment of patients with triple-negative and BRCA mutation—associated breast cancers. These developments are very promising and suggest that major advances in the targeted treatment of patients with triple-negative breast cancer are in sight. This review provides an overview of the clinical features of triple-negative breast cancer and current treatment strategies in the adjuvant setting. Mechanisms of DNA repair and the DNA damage response are reviewed to provide background for understanding novel approaches targeting DNA repair defects in this disease with DNA-damaging chemotherapeutic agents and poly(ADP-ribose) polymerase inhibitors. Ongoing studies, including those investigating the role of antiangiogenic therapies, are also reviewed.