Abstract P2-12-16: Use of ovarian function suppression to preserve fertility during neoadjuvant chemotherapy oncologically safe in women under age 40: An inverse probability weighting adjusted analysis

Abstract

Abstract Backgrounds Ovarian function suppression by gonadotropin releasing hormone agonist (GnRHa) is used to preserve fertility during neoadjuvant chemotherapy (NCT) in breast cancer especially in young women. Some results showed that patients with hormone-receptor (HR) negative breast cancer treated with NCT concurrent with GnRHa to preserve fertility had better outcome than without GnRHa. Methods From 2011 to 2014, 296 women aged under 40 years old with stage I to IIIA breast cancer, treated with NCT before surgery were analyzed. Primary endpoint was rate of pathologic complete response (pCR). Secondary endpoint was disease free survival (DFS) and overall survival (OS) between two groups categorized by concurrent with GnRHa during NCT to preserve fertility. Subgroup analysis was done with different HR status. Results Ninety-eight patients (33.1%) received concurrent GnRHa with NCT. Baseline characteristic showed no different between two groups except younger age with GnRHa group (p<0.001) and more use of GnRHa in HR+/HER2- subtype (p=0.023). pCR rate was higher with GnRHa group (8.08% vs 20.41%, p=0.002). However there was no significant difference in 5yr DFS between without GnRHa and with GnRHa (HR 1.4 95% CI 0.60 2-3.582) in entire cohort. In HR positive subcohort, 5yr DFS was not different between without GnRHa and with GnRH a group (80.9% and 87.7% respectively,p=0.643). In HR negative subcohort, 5yr DFS was 71.6% vs 70.6% (p=0.931). There were no overall survival difference between two group in entire and subcohort (p>0.05). Multivariable analysis also did not show survival improvement after use of GnRHa in HR- subtype (hazard ratio 2.166, (95% CI 0.746-6.292), p=0.155) and HR+ subtype (hazard ratio 1.231, (95% CI 0.205-7.411), p=0.820). Conclusion Among young women with breast cancer with negative hormone receptor treated with concomitant GnRHa achieved more pCR com compared with no GnRHa during chemotherapy. This result did not reach out to better survival outcome at this point. Trend to better outcome seen in survival curve implies further evaluation in this particular population. Citation Format: Young Joo Lee, Seonok Kim, Hee J Kim. Use of ovarian function suppression to preserve fertility during neoadjuvant chemotherapy oncologically safe in women under age 40: An inverse probability weighting adjusted analysis [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-12-16.