Impact on disease-free survival of the duration of ovarian function suppression, as postoperative adjuvant therapy, in premenopausal women with hormone receptor-positive breast cancer: a retrospective single-institution study.

INTRODUCTION: Although tamoxifen (TAM) plus ovarian function suppression (OFS) is considered as a standard adjuvant treatment for premenopausal women with hormone receptor-positive breast cancer, the optimal duration of OFS has not yet been established. This retrospective study was designed to assess the duration of OFS and the impact of the duration of OFS on the DFS in these patients.

METHODS: We retrospectively reviewed the data of premenopausal patients with breast cancer who received TAM + OFS (goserelin or leuprorelin) as adjuvant therapy between February 2004 and June 2015. The primary analysis was a comparison of the disease-free survival (DFS) between patients who received OFS for 3 years or less (OFS ≤ 3 years group) and those who received OFS for longer than 3 years (OFS > 3 years group).

RESULTS: We analyzed the data of 215 premenopausal patients diagnosed as having hormone receptor-positive breast cancer. A propensity score-matched model showed the absence of any significant difference in the DFS between the OFS ≤ 3 years group and OFS > 3 years group (6-year DFS rate, 93.2 vs. 94.0%; log-rank test p = 0.767).

CONCLUSIONS: Our data showed that among premenopausal women with hormone receptor-positive breast cancer who received TAM + OFS as adjuvant endocrine therapy, there was no significant difference in the DFS between the OFS ≤ 3-year group and OFS > 3-year group. A randomized trial is needed to establish the optimal duration of OFS for these patients.