Practice Changing or “Practice Confounding”? Pivotal Breast Cancer Data Raise Big Questions

Findings from the SERENA-6 trial, which examined switching therapies in patients with breast cancer ahead of disease progression, made headlines during the 2025 American Society of Clinical Oncology Annual Meeting. However, big questions remain. “I don’t know for sure if the approach is practice changing yet. I think the approach is practice confounding,” said Stephanie Graff, MD, director of breast oncology at Brown University Health Cancer Center in Providence, Rhode Island. Dr. Graff discussed the high-profile data with Robert A. Figlin, MD, the interim director of Cedars-Sinai Cancer in Los Angeles and Steven Spielberg Family Chair in Hematology-Oncology. The trial showed a progression-free survival benefit when patients switched from an aromatase inhibitor to camizestrant, based on circulating tumor DNA information. And yet, issues with the study’s design may make taking the results into clinic challenging. “We don’t have clear evidence on how changing based on molecular therapy changes overall survival,” said Dr. Graff. “I think we’re going to get there, but I don’t know that the point we are at with SERENA-6 has us there.”