Background: Central nervous system (CNS) metastases represent a devastating complication for advanced breast cancer patients. This observational study examines the influence of patient, tumour and treatment characteristics on overall survival after synchronous or metachronous CNS metastases.
Methods: Information on 992 breast cancer patients with CNS metastases (whose primary tumour was diagnosed between 2004 and 2010) was retrieved from the Netherlands Cancer Registry (NCR). Overall survival was calculated from the date of CNS metastatic diagnosis, and the impact of prognostic factors on survival was assessed using univariate and multivariate extended Cox-regression models.
Results: We identified 165 patients with synchronous and 827 patients with metachronous CNS metastases. The majority of patients (88%) presented with brain metastases only, 12% had leptomeningeal metastases. Overall median survival was 5.0 months. Non-triple-negative breast cancer and systemic therapy were associated with improved survival in both groups. In patients with synchronous CNS metastases, surgery for the primary tumour and the metastases also improved survival. In patients with metachronous metastases, younger age (<50 years), lower initial tumour stage (I), ductal carcinoma, a prolonged time interval until diagnosis of CNS metastasis (>1 year), and absence of extracranial metastases were associated with improved survival. Metastasectomy and radiation therapy did not provide benefit beyond the first six months.
Conclusions: No difference in survival was established between synchronous and metachronous CNS metastases. Triple-negative disease is prognostically unfavourable in both groups, while those receiving treatment have a better outcome. Metastasectomy and radiotherapy improve survival within the first six months, and additional benefit may be derived from systemic therapy.
Keywords: Brain metastases; Breast cancer; Central nervous system; Prognostic factors; Survival.
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