Risk-based Approaches for Optimizing Treatment in HER2-Positive Early Stage Breast Cancer

Advancements in the care for patients with early stage HER2-positive breast cancer is a story of incremental successes aimed at optimizing efficacy and reducing the toxicities of administered therapies. HER2 drives an aggressive breast cancer subtype that represents 15%–20% of breast cancers, for which HER2-targeted therapy is very active. In addition to trastuzumab, pertuzumab, neratinib, and ado-trastuzumab emtansine have been approved in recent years for the treatment of high-risk early stage HER2-positive breast cancer. As a result of both a high response rate to neoadjuvant therapy and the opportunity for response-adapted adjuvant therapy, the treatment paradigm has evolved so that most patients with stage II and III disease now receive neoadjuvant therapy. Additionally, the efficacy of HER2-therapy allows for de-escalation of treatment in many patients with stage I disease. As a result, multidisciplinary evaluation is essential for the optimal care of patients with HER2-positive breast cancer. Important areas of further research include tailoring the duration and intensity of therapy based on disease risk and response to neoadjuvant therapy. This article will review the evaluation of patients with early stage HER2-positive breast cancer and provide an evidence- and guideline-based summary of risk-based treatment strategies.