Intraventricular metastatic brain tumors account for a small but challenging fraction of metastatic brain tumors (0.9-4.5%). Metastases from renal cell carcinoma (RCC) account for a large portion of these intraventricular tumors, and while patient outcomes are assumed to be poor, these have not been reported in a modern series with a multimodality treatment paradigm including radiation, resection and CSF diversion. Here we present the first case series of patients with intraventricular metastatic tumors from renal cell carcinoma.
This is a single institution retrospective review of patients with intraventricular RCC metastases treated between January 2003 and January 2019. Volumetric analysis was used to delineate tumor size, and the Kaplan-Meier method was used to evaluate survival data.
Twenty-two intraventricular RCC metastases were identified in 19 patients with 61.3 patient-years of follow up. The median patient age was 64 years, and the median tumor volume was 2.2 cm. Overall, 19 metastases were treated initially with radiation. Of these, 16 received stereotactic body radiotherapy (SBRT) and 3 metastases received whole brain radiotherapy. Three tumors were surgically excised and received adjuvant SBRT in the upfront setting. While five patients presented with obstructive hydrocephalus, none required cerebrospinal fluid (CSF) diversion. Following treatment, 5 metastases progressed, resulting in 1- and 3-year progression free survival (PFS) rates of 81.6% and 68%, respectively. The median overall survival was 2.8 years, with 1- and 5-year overall survival rates of 76.7% and 28.3%, respectively. Leptomeningeal carcinomatosis was not observed.
Despite relatively limited overall survival for this population with metastatic cancer, comparable to contemporary parenchymal brain metastasis cohorts, reasonable local CNS control was achieved in the majority of patients using a paradigm of focal irradiation and resection where indicated. Importantly, CSF diversion was not required even in patients presenting with hydrocephalus.

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