Patient-Reported Outcomes and Future Research Directions in HER2-Positive Metastatic Breast Cancer

Dr. Rao acknowledges encouraging patient-reported outcomes data from clinical trials while noting potential differences between trial populations and real-world patients. Racial diversity limitations in trials and international study conduct may not reflect community practice populations, making real-world evidence collection crucial.

Dr. Kruse identifies ongoing subgroup analyses as critical for refining patient selection strategies. She notes the complex interplay between escalation and de-escalation concepts in HER2-positive breast cancer, where treatment intensification competes with personalization approaches.

The challenge involves determining optimal treatment for intermediate-risk patients, such as those with 2-centimeter node-negative or single-node-positive disease. High-risk patients present clearer treatment decisions, but gray-zone cases require careful consideration.

Current FDA approvals are broader than original clinical trial inclusion criteria, creating potential for inappropriate treatment intensification without clear risk stratification tools. Better biomarkers beyond absence of pathologic complete response after neoadjuvant therapy are needed.

Long-term biomarker development hopes include improved risk assessment tools that guide toxicity exposure decisions for patients most likely to benefit. Current anatomic staging provides insufficient biological risk characterization.

The panel anticipates neoadjuvant event-free survival data and longer-term follow-up information to guide treatment selection. Integration of T-DXd across neoadjuvant and adjuvant settings will require rethinking sequential treatment approaches.

Questions remain about using T-DXd in both neoadjuvant and adjuvant settings for patients with residual disease, and how to preserve the drug's efficacy for eventual metastatic use in patients who recur despite intensive early treatment.