Abstract P1-08-23: Androgen receptor as predictive marker for pathologic complete response in breast cancer with neoadjuvant chemotherapy

Abstract

Abstract Background: Androgen receptors (AR) has emerged as a prognostic factor predicting survival and recurrence in breast cancer. However, the role of AR as a predictor of pathological complete response (pCR) rate after neoadjuvant chemotherapy by subtypes is unclear. This study aimed to investigate according to AR in breast cancer patients undergoing neoadjuvant chemotherapy as a predictor. Furthermore, we estimated the relationship between AR expression and clinicopathological factors. Method: We identified 624 breast cancer patients who underwent surgery after neoadjuvant chemotherapy at the National Cancer Center from April 2016 to October 2019. We retrospectively collected the medial records that the clinicopathologic information and AR expression analyzed according to cancer stage, hormonal receptor status, HER2 status, tumor subtype, pCR. Results: Among the 624 breast cancer patients, 529 (84.8%) were AR positive patients and 95 (15.2%) were AR negative patients. The mean age of the patients was 50.0 years. The rate of pCR was 31.4% (196/624). AR negative patients had significantly high rate of pCR than AR positive patients. (AR (-) 43.2% vs. AR (+) 29.3%, p = 0.0074). AR positive patients showed more ER positivity, PR positivity, HER2 positivity and luminal A subtype. A higher proportion of AR positive patients compared to AR negative patients received target therapy and hormonal therapy (target therapy, AR (-) 15.8% vs. AR (+) 43.9%, hormonal therapy, 14.7% vs. 71.0%, p <.0001). The tumor factors associated with pCR were early stage, histologic grade 3, ER negativity, PR negativity, AR positivity, HER2 positivity, and high ki-67%. According to subtypes of tumor, the correlation between AR expression and pCR was. significantly higher in AR negative luminal A type (AR (-) 28.57% vs. AR (+) 7.26%, p =0.0215). The other subtypes did not show a statistically significant difference. Conclusion: This study shows that AR expression is predominant in luminal A subtype. When determining neoadjuvant chemotherapy in luminal A subtype, AR expression can be considered as a pCR predictive marker. Citation Format: Eun-Gyeong Lee, Dong-Eun Lee, Jai Hong Han, Seeyoun Lee, Han-Sung Kang, Eun Sook Lee, Youngmee Kwon, Hyun Hee Kim, Hee Jung Chae, Sung Hoon Sim, Keun Seok Lee, So-Youn Jung. Androgen receptor as predictive marker for pathologic complete response in breast cancer with neoadjuvant chemotherapy [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 P1-08-23.