Survival Outcome of Combined GnRH Agonist and Tamoxifen Is Comparable to That of Sequential Adriamycin and Cyclophosphamide Chemotherapy Plus Tamoxifen in Premenopausal Patients with Lymph-Node–Negative, Hormone-Responsive, HER2-Negative, T1-T2 Breast Cancer

PURPOSE: The purpose of this study was to compare treatment outcomes between combined gonadotropin-releasing hormone agonist and tamoxifen (GnRHa+T) and sequential adriamycin and cyclophosphamide chemotherapy and tamoxifen (AC->T) in premenopausal patients with hormone-responsive, lymph-node–negative breast cancer. MATERIALS AND METHODS: In total, 994 premenopausal women with T1-T2, lymph-node–negative, hormone-receptor-positive, HER2-negative breast cancer between January 2003 and December 2008 were included in this retrospective cohort study. GnRHa+T and AC->T were administered to 608 patients (61.2%) and 386 patients (38.8%), respectively. Propensity score matching and inverse probability weighting were applied to the original cohort, and 260 patients for each treatment arm were included in the final analysis. Recurrence-free, cancer-specific, and overall survival was compared between the two treatment groups. RESULTS: A total of 994 patients were followed up for a median of 7.4 years (range, 0.5 to 11.4 years). The 5-year follow-up rate was 98.7%, and 13 patients were lost to follow-up. In propensity-matched cohorts (n=520), there was no difference in recurrence-free, cancer-specific, and overall survival rates between the two treatment groups (p=0.306, p=0.212, and p=0.102, respectively), and this was maintained after applying inverse probability weighting. CONCLUSION: GnRHa+T is a reasonable alternative to AC->T in patients with premenopausal, hormone-responsive, HER2-negative, lymph-node–negative, T1-T2 breast cancer.