Adding Ovarian Suppression to Tamoxifen to Reduce Recurrence in Younger Women With Breast Cancer

By: Celeste L. Dixon
Posted: Thursday, November 16, 2023

Analysis of the long-term, post-trial outcomes of about 1,500 ASTRRA participants has indicated that adding ovarian function suppression to tamoxifen should be considered for women up to age 45 with hormone-sensitive breast cancer who remain in a premenopausal state or resume ovarian function after chemotherapy. As described in the Journal of Clinical Oncology, the study demonstrated a disease-free survival benefit—although no significant improvement in overall survival—with this therapeutic strategy, according to Hee Jeong Kim, MD, PhD, of the University of Ulsan College of Medicine, Seoul, South Korea, and colleagues.

“At 106.4 months of median follow-up, there was a continuous significant reduction in the disease-free survival event rate, [the primary endpoint,] in the [combination] group,” stated the team. The 8-year disease-free survival rate was 85.4% in the combination group vs 80.2% in those taking tamoxifen alone (hazard ratio [HR] = 0.67), which the authors characterized as “meaningful reductions in recurrences.”

The ASTRRA study involved 1,483 premenopausal women who were treated with definitive surgery after completing adjuvant or neoadjuvant chemotherapy for estrogen receptor–positive breast cancer. Patients were randomly assigned on a 1:1 basis to complete 5 years of tamoxifen alone or 5 years of tamoxifen with ovarian function suppression for 2 years. The secondary endpoint of this new analysis was overall survival, and as mentioned, the rates did not significantly differ between the two groups: 96.5% with the combination and 95.3% with tamoxifen alone (HR = 0.78). These rates highlight the ”overall excellent prognosis in this population,” wrote the team.

Returning to the primary endpoint, “the findings support the possibility of endocrine therapy tailored to an appropriate subset of women who may benefit from adding 2 years of ovarian function suppression to tamoxifen,” concluded Dr. Kim and co-investigators. “Personalizing treatment decisions requires an individual risk assessment and consideration of long-term toxicities.”

Disclosure: The study authors’ disclosure information can be found at ascopubs.org.

Journal of Clinical Oncology

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