Meningeal metastases in prostate cancer: Institutional series and comprehensive systematic review

Meningeal metastases (MM) are a rare progression in advanced prostate. Here we aimed to characterize the incidence, clinical presentation, and outcomes of patients with MM, including dural and leptomeningeal metastases, from primary prostate cancer. A systematic search was performed on MEDLINE, EMBASE, Scopus, and Web of Science. Studies that included patients who developed MM from primary prostate cancer were abstracted. Assessed outcomes included time from primary cancer to MM and MM to death, and clinical presentation of MM, among others. Case reports were compared qualitatively, while observational studies were pooled for quantitative synthesis. The systematic review was prospectively registered on PROSPERO (CRD42020205378). Our institutional series, 11 observational studies, and 46 case reports were synthesized, comprising a total of 191 patients. From the observational studies, the mean age at developing MM was 63.0 years (range: 58.4, 70.9). Presenting neurological symptoms were variable and largely depended on location of MM. The mean time from prostate cancer to MM was 54.6 months (range: 21.0, 101.5), and the mean time from MM to death was 9.0 months (range: 2.6, 23.0). Patients requiring resection for MM had shorter survival after disease progression compared to patients receiving radiation or supportive therapy. All articles had at least moderate risk of bias. We describe the largest synthesis of patients with progression to MM from prostate cancer. Current evidence is very low-quality and primarily stems from small observational studies. Neurological symptoms in the setting of advanced prostate cancer, especially in high-risk disease, warrants radiographic imaging for MM. Further prospective research on risk factors and treatment for MM is warranted.