Real world initial palliative treatment patterns and clinical outcomes in premenopausal patients with hormone receptor-positive, HER2-negative metastatic breast cancer: A study of the National Cancer Center, China

BACKGROUND: To observe whether guideline non-adherence in initial palliative treatment choices for premenopausal hormone receptor-positive (HR+), HER2-negative metastatic breast cancer (MBC) patients result in worse clinical outcomes in the Chinese population. METHODS: The China National Cancer Center database was used to identify 2194 patients diagnosed between 2004 and 2015. A total of 451 premenopausal patients with HR + HER2- MBC were included. Clinicopathological features and survival information were extracted. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method and compared using log-rank test. RESULTS: The number of patients receiving initial chemotherapy, endocrine therapy and chemo-endocrine therapy 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 and more liver metastasis, compared with patients receiving initial endocrine therapy. Both PFS and OS were significantly longer for chemo-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), and chemotherapy group (median PFS 7.1 months and OS 43.9 months). In multivariate analysis, none of the three treatment strategies were independently associated with PFS or OS. CONCLUSION: 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. Further studies with larger sample size across China are needed to explore the relationship between this guideline non-adherence and clinical outcomes.