Systemic Therapy Considerations in Older Adults With Early-Stage Breast Cancer

Importance: The treatment of older adults with chemotherapy for early-stage breast cancer involves a complex decision-making process that weighs the competing risks of disease recurrence against the potential harms of treatment. While older adults continue to be underrepresented in therapeutic clinical trials, there is a growing body of evidence to support optimal management of each subtype of early-stage breast cancer, including novel strategies like adjuvant cyclin-dependent kinase 4/6 inhibitors in hormone receptor-positive disease, and the neoadjuvant use of pembrolizumab in triple-negative breast cancer. Observations: The available evidence to support the systemic management of early-stage breast cancer in older adults with consideration of the data gaps for cytotoxic chemotherapy, de-escalated regimens, and targeted therapies is reviewed, and tools to optimize decision-making and supportive care for older adults with early breast cancer are presented. Clinicians should aim to avoid overtreatment when available evidence suggests a less intensive approach may suffice for a lower-risk cancer, and/or the patient is at high risk of serious toxic effects from chemotherapy treatment. On the other hand, undertreatment without consideration of the potential downsides may increase breast cancer-related mortality in older patients with higher-risk cancers. Conclusions and Relevance: This review will help clinicians best use the available data and decision-making tools to support best practice for treating older adults with early-stage breast cancer and will highlight ongoing clinical trials aimed at optimizing medical care for this patient population.