Addition of Ovarian Suppression to Adjuvant Tamoxifen Significantly Improved DFS Among Premenopausal Patients With ER-Positive Breast Cancer

Post-trial follow-up results from the ASTRRA trial showed the addition of ovarian function suppression to adjuvant tamoxifen significantly improved disease-free survival (DFS) rate with no negative impact on overall survival (OS) among premenopausal patients with estrogen receptor (ER)-positive breast cancer treated with definitive surgery after completion of adjuvant or neoadjuvant chemotherapy.

“The follow-up data of the ASTRRA trial were limited to 5 years,” according to Soo Yeon Baek, MD, MSc, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea, and coauthors. “In this study, we present the results from the post-trial follow-up of the ASTRRA trial … after a median follow-up of 8 years.”

In this analysis, 1,483 premenopausal patients younger than 45 with ER-positive breast cancer, previously treated with definitive surgery after completion of adjuvant or neoadjuvant chemotherapy, were randomized on a 1-to-1 basis to receive either 5 years of tamoxifen plus 2 years of ovarian function suppression, or 5 years of tamoxifen alone. The primary end point was DFS and the secondary end point was OS. 

At the median follow-up of 106.4 months, researchers observed a continuous, significant reduction in DFS event rate among patients treated with tamoxifen plus ovarian function suppression. The 8-year DFS rate was 85.4% among patients treated with tamoxifen plus ovarian function suppression and 80.2% among patients treated with tamoxifen alone. OS rate was 96.5% and 95.3%, respectively. 

“Our study demonstrated a consistent DFS benefit for patients with hormone receptor–positive breast cancer who remained premenopausal or regained ovarian function after chemotherapy using [ovarian function suppression] with [tamoxifen] for 2 years,” stated Dr Baek and coauthors. “The ASTRRA trial highlights both the power of [ovarian function suppression] in young patients with estrogen receptor-positive disease and the overall excellent prognosis in this population.”

Source:

Baek SY, Noh WC, Ahn SH, et al. Adding ovarian suppression to tamoxifen for premenopausal women with hormone receptor–positive breast cancer after chemotherapy: An 8-year follow-up of the ASTRRA trial. J Clin Oncol. Published online: August 22, 2023. doi:10.1200/JCO.23.00557