Clinical Outcomes in Patients with Renal Cell Carcinoma Metastases to the Choroid Plexus

OBJECTIVE: 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. Although patient outcomes have been assumed to be poor, these have not been reported in a modern series with a multimodality treatment paradigm of radiotherapy (RT), resection, and cerebrospinal fluid (CSF) diversion. We have presented the first case series of patients with intraventricular metastatic tumors from RCC. METHODS: We performed a single-institution retrospective review of patients with intraventricular RCC metastases treated from January 2003 to January 2019. Volumetric analysis was used to delineate the tumor size and the Kaplan-Meier method to evaluate the survival data. RESULTS: A total of 22 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(3). Overall, 19 metastases had been treated initially with RT. Of these, 16 had received stereotactic body RT and 3 had received whole brain RT. Three tumors were surgically excised and had received adjuvant stereotactic body RT in the upfront setting. Although 5 patients had presented with obstructive hydrocephalus, none had required CSF diversion. After treatment, 5 metastases had progressed, resulting in 1- and 3-year progression-free survival 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. CONCLUSIONS: Despite the relatively limited overall survival for this population with metastatic cancer, comparable to contemporary parenchymal brain metastasis cohorts, reasonable local central nervous system control was achieved in most patients using a paradigm of focal RT and resection, where indicated. Finally, CSF diversion was not required even in patients presenting with hydrocephalus.