An exploratory analysis of the phase 3 HERA trial indicates that ovarian function suppression (OFS) in conjunction with endocrine therapy significantly improves long-term survival outcomes for premenopausal women with HER2-positive, hormone receptor (HR)-positive breast cancer. The findings, presented at the 2024 European Society for Medical Oncology (ESMO) Congress, suggest a potential benefit for selected patients with high-risk disease features.
The study, led by Dr. Sung Gwe Ahn from the Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea, assessed data from the HERA trial (NCT00045032) to determine if adding OFS to endocrine therapy provided a survival advantage. The results demonstrated a clinically meaningful improvement in both disease-free survival (DFS) and overall survival (OS).
Improved Survival Outcomes
With a median follow-up of 11 years, the 10-year DFS rate was 70.9% in patients who received endocrine therapy plus OFS, compared to 59.6% with tamoxifen alone (HR, 0.68; 95% CI, 0.53-0.88). The 10-year overall survival rates also favored the OFS group, with 84.7% survival compared to 74.0% in the tamoxifen-only group (HR, 0.64; 95% CI, 0.46-0.89).
Considerations for Toxicity and Patient Selection
Dr. Ahn noted that administering OFS can be challenging, particularly for patients who have already undergone chemotherapy and anti-HER2 therapies, due to potential toxicity. He emphasized the importance of carefully selecting patients who are most likely to benefit from OFS, particularly those with high-risk disease characteristics. "For premenopausal, young [patients with] HR-positive, HER2-positive breast cancer, they need ovarian function suppression in conjunction with endocrine therapy, especially if the patient has high-stage [disease] and some high-risk features," Dr. Ahn stated.
Implications for Clinical Practice
The findings from this exploratory analysis suggest that OFS should be considered as part of the treatment strategy for premenopausal women with HER2-positive, HR-positive breast cancer, especially those with high-risk features. However, clinicians should carefully weigh the potential benefits against the risks of toxicity and patient adherence when making treatment decisions. Further research is warranted to identify the specific patient subgroups that are most likely to benefit from the addition of OFS to endocrine therapy.
