Abstract P2-14-04: Co-Administration of GnRH-Agonists with Adjuvant Chemotherapy in Young Breast Cancer Patients: The Effect on Ovarian Function and on Clinical Outcome

Abstract

Abstract Background: Loss of fertility is a major concern for young breast cancer (BC) patients who require adjuvant chemotherapy. The risk of ovarian failure depends on patient's age and chemotherapy regimen. Use of GnRH agonists (GnRHa) has been proposed as a mean for ovarian function preservation but has been investigated mainly in small single arm studies. Objectives: To evaluate ovarian function preservation and disease free survival (DFS) in young breast cancer patients following GnRHa and adjuvant chemotherapy co-administration. Methods: In this multicenter retrospective study, we reviewed medical records of 560 breast cancer patients diagnosed before the age of 40, from 1990 through 2006. All patients were treated in one of 5 Israeli cancer centers with standard adjuvant or neoadjuvant chemotherapy regimens with curative intent. GnRHa were prescribed at the discretion of the treating physician. Ovarian function preservation was determined by resumption of menses, premenopausal hormonal profile or pregnancy during follow up. Multivariate analysis was applied in order to determine whether coadministration of GnRHa with chemotherapy affects DFS. Results: Data was available for 71 patients who received GnRHa during chemotherapy (group A), 60 of those were evaluable for fertility and 68 were evaluated for DFS. The group not receiving GnRHa included 460 patients (group B). Of those 207 were evaluable for fertility and 370 for DFS. Data concerning patients’ characteristics and outcome in each group are presented in the table 1. In a Cox regression model including age, stage, ER/PR status and GnRHa administration, the latter variable predicted a better DFS rate (RR 0.31; 95% CI 0.16-0.70; p=0.003), excluding the subgroup with ER/PR positive tumors (p=0.128). This probably reflects selection bias of prognostic factors not included in the analysis and not a real anti neoplastic hormonal effect. Conclusions: Patients who received GnRHa were younger and had less advanced disease. Fertility was preserved independent of GnRHa administration and regardless of cumulative doses of cyclophosphamide or taxans. This observation suggests that GnRHa are unnecessary for fertility preservation in patients younger than 40yrs. No detrimental effect of GnRHa during chemotherapy was observed on disease outcome. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-14-04.