Phase 3 trial of adding ovarian suppression to tamoxifen after chemotherapy for premenopausal HR-positive breast cancer: 8-year follow-up

The multicenter phase 3 ASTRRA trial in South Korea included women youger than 45 years with hormone receptor-positive breast cancer treated with definitive surgery and neoadjuvant and adjuvant chemotherapy who remained premenopausal or regained ovarian function. Patients were randomized to five years of tamoxifen plus two years ovarian function suppression (TAM+OFS) or five years of TAM-only. Long-term follow-up of the trial found that the 8-years DFS rate was 85.4% in the TAM+OFS group versus 80.2% in the TAM-only group (HR 0.67; 95% CI 0.51-0.87). The 8-years OS rate was high in both groups without statistical significant difference (96.5% versus 95.3%). The authors conclude that adding OFS to TAM should be considered for this patient population.