In real life, one-quarter of patients with hormone receptor-positive metastatic breast cancer receive chemotherapy as initial palliative therapy: a study of the Southeast Netherlands Breast Cancer Consortium

Background: The objective of this study was to present initial systemic treatment choices and the outcome of hormone receptor-positive (HR+) metastatic breast cancer. Patients and methods: All the 815 consecutive patients diagnosed with metastatic breast cancer in 2007-2009 in eight participating hospitals were identified. From the 611 patients with HR+ disease, a total of 520 patients with HER2-negative (HER2-) breast cancer were included. Initial palliative systemic treatment was registered. Progression-free survival (PFS) and overall survival (OS) per initial palliative systemic therapy were obtained using the Kaplan-Meier method and compared using the log-rank test. Results: From the total of 520 patients with HR+/HER2-metastatic breast cancer, 482 patients (93%) received any palliative systemic therapy. Patients that received initial chemotherapy (n = 116) were significantly younger, had less comorbidity, had received more prior adjuvant systemic therapy and were less likely to have bone metastasis only compared with patients that received initial endocrine therapy (n = 366). Median PFS of initial palliative chemotherapy was 5.3 months [95% confidence interval (CI) 4.2-6.2] and of initial endocrine therapy 13.3 months (95% CI 11.3-15.5), with a median OS of 16.1 and 36.9 months, respectively. Initial chemotherapy was also associated with worse outcome in terms of PFS and OS after adjustment for prognostic factors. Conclusions: A high percentage of patients with HR+ disease received initial palliative chemotherapy, which was associated with worse outcome, even after adjustment of relevant prognostic factors.