208P Clinical characteristics and prognostic factors in patients with breast cancer and leptomeningeal metastases: A subanalysis of the German brain metastases in breast cancer registry (BMBC)

Abstract

Leptomeningeal metastases (LM) in patients with breast cancer (BC) is rare but associated with poor prognosis. Specific factors associated with prognosis of patients with LM have not been characterized in a large patient cohort. We aimed to evaluate prognostic factors in BC patients with LM from the Brain Metastases in Breast Cancer (BMBC) Registry. Patient’s and tumor’s main features were retrieved from the BMBC. Median overall survival (mOS) was defined as the time from first diagnosis of central nervous system metastases (CNS) to death from any cause. Median progression-free survival (mPFS) was defined as the time from first diagnosis of CNS to progression in CNS, extracranial metastases or death. A total of 781 patients with LM and BC were included in the analysis (781/3858, prevalence of 20.2%). 354 (45.3%) patients had LM without BM. A mPFS was3.9 months (95%CI 3.4-4.5) and a mOS was 4.9 months (95% 4.3-5.7). Older age (>=60 vs. <60 years, HR 2.07, 95%CI 1.53-2.79) and a worse ECOG performance status (2-4 vs. 0-1 HR 2.03, 95% CI 1.52-2.71) were significantly associated with a higher risk of death in the multivariate analysis. Endocrine treatment (for hormone-receptor-positive BC) was significantly associated with a lower risk of death (HR 0.43 95%CI 0.28-0.65). Also, whole brain radiotherapy was associated with a lower risk of death (HR 0.62 95%CI 0.45-0.87). Furthermore, BC subtype correlated significantly with prognosis in patients with LM. Patients with luminal-like BC and patients with a triple negative BC had a significant higher risk of death than patients with a triple-positive BC (HR 1.55, 95%CI 1.05-2.28 resp. HR 2.47, 95%CI 1.59-3.85). Additional analyses, including a comparison with patients without LM in the BMBC cohort will be presented. Patients with LM have a short survival. The identified prognostic factors can support the clinicians to identify the group of patients with a better survival who could possibly benefit from a more intense treatment regimen. Financial support for the management of BMBC Registry was provided by an unrestricted research grant from Daiichi Sankyo to GBG.