Abstract P5-13-06: Concurrent gonadotropin-releasing hormone (GnRH) agonist administration with chemotherapy improves neoadjuvant chemotherapy responses in young premenopausal breast cancer patients

Abstract

Abstract Background Gonadotropin-releasing hormone (GnRH) agonist therapy for ovarian function preservation shows promising results. This study aimed to determine the oncologic efficacy of GnRH agonist treatment concurrent with chemotherapy in a neoadjuvant setting. Patients and Methods A retrospective analysis was performed on 332 cases of invasive breast cancer in patients who were <40 years old at diagnosis and received GnRH agonists concurrent with neoadjuvant chemotherapy (GnRH agonist group) or neoadjuvant chemotherapy alone (neochemotherapy-alone group) at Asan Medical Center from December 2010 to September 2014. Pathologic complete response rates (pCR) and Ki-67 changes were evaluated between the two groups. For hormone receptor (HR)-positive tumors, the clinical response and preoperative endocrine prognostic index (PEPI) score also were evaluated. Results The median age was 32 ± 3.9 and 36 ± 3.0 years old in the GnRH agonist group and neochemotherapy-alone group, respectively (P < .001). Adjusted for tumor size, grade, lymph node metastasis, HR status, and chemotherapy regimen, the GnRH agonist group exhibited a higher pCR rate with an odds ratio (OR) of 2.98 (95% CI, 1.37–6.34) and more decreased Ki-67 expression during treatment (P = 0.05) than the neochemotherapy-alone group. In HR-negative tumors, the GnRH agonist group showed a higher pCR rate (multivariate OR = 3.50; 95% CI, 1.37–8.95) and more decreased Ki-67 expression (P = 0.047). In HR-positive breast cancer, the pCR rate, change in Ki-67 index, and clinical response were higher and preoperative prognostic index (PEPI) scores were lower in the GnRH agonist group, but not significant between the two treatment groups. Conclusion Concurrent administration of GnRH agonists during neoadjuvant chemotherapy improved pCR rates and suppressed Ki-67 expression especially in HR-negative tumors. Citation Format: Yoon TI, Kim HJ, Yu JH, Sohn G, Ko BS, Lee JW, Son BH, Ahn SH. Concurrent gonadotropin-releasing hormone (GnRH) agonist administration with chemotherapy improves neoadjuvant chemotherapy responses in young premenopausal breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-13-06.