Prostate Cancer Central Nervous System Metastasis in a Contemporary Cohort

Importance Central Nervous System (CNS) metastasis from prostate cancer (PCA) is a rare event, but one with significant prognostic impact for those affected. There are limited data on its impact in contemporary cohorts treated with modern agents. Design A retrospective institutional review was performed to characterize the occurrence/outcome of PCA CNS metastasis on all cases of PCA from 2011-2017. A manual chart review was performed to confirm PCA CNS metastases in all cases identified through a diagnostic code screening of the health data. Results 6,596 cases of PCA were identified, with 29 (20 dural and 9 intraparenchymal) confirmed cases of CNS metastases from prostate cancer. The median survival from the time of diagnosis of CNS metastasis was 2.6 (95%CI: 2.04 – 10.78) months and 5.41 (95% CI: 3.03 – not reached) months for dural and parenchymal metastases respectively. Among those who developed CNS metastases, approximately 79% of patients had prior exposure to abiraterone and/or enzalutamide, of whom 50% had ≥6 months of exposure. Four of the 5841 (0.07%) patients developed CNS metastases prior to the initiation of therapy or on androgen deprivation therapy (ADT) alone. In contrast, 24 of the 279 (8.6%) patients with 2 or more lines of medical therapy developed CNS metastases. Conclusions and Relevance: Our analysis highlights the continued poor prognosis of parenchymal and dural CNS metastases from PCA. CNS metastases in prostate cancer remain a rare event with a 0.4% incidence in this series, but this incidence is considerably increased in patients who receive medical therapy beyond first line ADT.