A new cohort study demonstrated that extended adjuvant endocrine therapy (eET) lasting longer than 5 years was associated with significantly improved clinical outcomes in BRCA pathogenic variant carriers with hormone receptor-positive (HR+)/HER2- early breast cancer. These data were presented at the San Antonio Breast Cancer Symposium 2025.

While evidence for eET in BRCA carriers has been limited, this analysis investigated whether continuing treatment beyond the standard 5 years improves invasive disease-free survival (iDFS) and distant relapse-free interval (DRFI) in this high-risk population.

Researchers analyzed 1225 patients with stage I-III HR+/HER2- breast cancer, including 164 BRCA1/2 carriers. Compared with noncarriers, the BRCA group was younger (median age, 39 years) and presented with higher tumor stage and grade. 

Despite the higher baseline risk, BRCA carriers receiving eET achieved significantly better outcomes. eET was associated with a significant improvement in iDFS compared with standard-duration ET. 

The benefit also extended to distant recurrence. In BRCA carriers, eET was significantly associated with improved DRFI compared with ET of 5 years or less. 

Landmark analysis confirmed the durability of this protection over time. eET consistently improved DRFI at 60, 84, and 120 months, suggesting a sustained long-term benefit.

In this cohort of BRCA pathogenic variant carriers with HR+/HER2- early breast cancer, extended adjuvant ET (>5 years) was significantly associated with improved iDFS and DRFI compared to 5 years of ET. These findings support the potential benefit of prolonged endocrine therapy in this high-risk population.

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By Zia Sherrell

Reference: https://www.abstractsonline.com/pp8/#!/21392/presentation/193 

Disclosures: Co-author Elisabetta Munzone disclosed relationships with Exact Sciences, MSD Oncology, and others. The remaining authors declared no relevant financial disclosures. 

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