Comparison of survival outcome of concurrent GnRH agonist plus tamoxifen to that of sequential adriamycin and cyclophosphamide chemotherapy plus tamoxifen in premenopausal, lymph node-negative, hormone-responsive, HER2-negative, T1-2 breast cancer patients.

Abstract

137 Background: The purpose of this study was to compare treatment outcomes between gonadotropin-releasing hormone (GnRH) agonist plus tamoxifen and adriamycin and cyclophosphamide (AC)-containing chemotherapy plus tamoxifen in hormone-responsive, premenopausal, node-negative, breast cancer patients. Methods: Among 7278 breast cancer patients who were diagnosed as breast cancer at Asan medical center, Seoul, Korea, 994 premenopausal women with node-negative, hormone receptor-positive, HER2-negative, T1-2 breast cancers were included in this retrospective cohort study: A median follow-up was 7.4 years (range, 0.5-11.4 years). 608 patients (61.2%) were treated with GnRH agonist together with tamoxifen, and 386 patients (38.8%) were treated with AC-containing chemotherapy with tamoxifen. The propensity score matching and inverse probability weighting was applied to original cohort based on patients’ age, operation method, nuclear and histologic grade, estrogen receptor and progesterone receptor positivity, T stage, Her2 positivity, and p53 positivity. In final analysis, 260 patients for each treatment arm were included. Results: In propensity matched cohorts (n = 520), a total of 34 patients had recurrence. There were 5 cancer-specific deaths and 12 overall deaths among total 520 patients. There were no survival differences for recurrence-free survival (p= 0.306), cancer-specific survival (p= 0.212), and overall survival (p= 0.102) between the two treatment groups. After applying inverse probability weighting, there were no survival differences for recurrence-free survival (p = 0.522), cancer-specific survival (p= 0.154). However, GnRH agonist with tamoxifen arm showed better overall survival than AC chemotherapy with tamoxifen arm (p= 0.021). Conclusions: Adding GnRH agonist to tamoxifen is a reasonable alternative to adding AC chemotherapy to tamoxifen in premenopausal, hormone-responsive, HER2-negative, lymph node-negative, T1-2, breast cancer patients.