Abstract P1-16-06: In real world, a high percentage of premenopausal patients with hormone receptor-positive, HER2-negative metastatic breast cancer receive chemotherapy as first-line treatment: A study of the National Cancer Center, China
Authors: Li Yiqun , Mo Hongnan , Guan Xiuwen , Lin Shaoyan , Wang Zijing , Chen Yimeng , Chen Shanshan , Li Qiao , Cai Ruigang , Wang Jiayu , Luo Yang , Fan Ying , Yuan Peng , Zhang Pin , Li Qing , Ma Fei , Xu Binghe 
Published: March 2022

Abstract
Background: In this study, we aimed to observe initial palliative treatment choices and clinical outcomes for premenopausal hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer patients (MBC) in the Chinese population in real life.Methods: The China National Cancer Center database was used to identify 2194 MBC patients diagnosed between 2004 to 2015. Premenopausal patients with HR+ HER2- MBC were included. Clinicopathological features, initial palliative treatment choices and survival information were extracted. First-line progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method and compared using the log-rank test. Prognostic factors associated with OS were analyzed using Cox regression model with 95% confidence interval (95%C.I.).Results: A total of 451 premenopausal patients meeting study criteria were identified. Median age was 44 years. The number of patients receiving chemotherapy alone, endocrine therapy and chemotherapy followed by endocrine therapy as initial palliative treatment strategy were 222(49.2%), 80 (17.7%), and 149 (33.0%), respectively. Patients receiving initial chemotherapy were more likely to be luminal B subtype, had more de novo stage IV disease than recurrent disease and had more liver metastasis, compared with patients receiving initial endocrine therapy. Both PFS and OS were significantly longer for chemotherapy-endocrine therapy group (median PFS 18.9 months and OS 75.0 months), than for endocrine therapy group (median PFS 11.7 months and OS 53.5 months). Chemotherapy alone group presented with worst survival outcomes (median PFS 7.1 months and OS 43.9 months). However, in multivariate analysis, none of the three treatment strategies were independently associated with PFS or OS.Conclusions: In real world, a high percentage of premenopausal patients with HR+ HER2- disease received chemotherapy as initial palliative treatment in China, which was not associated with worsened survival. This unexpected guideline non-adherence reflects the unmet need of establishing treatment guidelines specifically for premenopausal patients in the Chinese population. Further studies with larger sample size across China are needed to explore the relationship between this guideline non-adherence and clinical outcomes.
Citation Format: Yiqun Li, Hongnan Mo, Xiuwen Guan, Shaoyan Lin, Zijing Wang, Yimeng Chen, Shanshan Chen, Qiao Li, Ruigang Cai, Jiayu Wang, Yang Luo, Ying Fan, Peng Yuan, Pin Zhang, Qing Li, Fei Ma, Binghe Xu. In real world, a high percentage of premenopausal patients with hormone receptor-positive, HER2-negative metastatic breast cancer receive chemotherapy as first-line treatment: A study of the National Cancer Center, China [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 P1-16-06.