Rates of occult brain metastases in patients (pts) with advanced renal cell carcinoma (RCC): A cohort study from patients treated across 22 clinical trials.

Abstract

673 Background: National guidelines for RCC management only recommend brain imaging ‘if clinically indicated’; the rate of occult brain metastases is not defined. Early detection of CNS disease has major implications as it typically triggers early intervention with the aim to limit morbidity, including major complications of local progression. In an effort to define the utility of brain screening, we investigated the rate of occult brain metastasis in a large cohort of metastatic RCC pts. Methods: We performed a retrospective review of completed and actively accruing metastatic RCC clinical trials conducted at Memorial Sloan Kettering Cancer Center. Individual charts of pts screening for those studies with mandatory brain imaging at baseline were reviewed to identify subjects harboring occult brain metastases. We collected patient demographics, International Metastatic Database Consortium (IMDC) risk status, sites of metastatic disease, and tumor histology. Patients with neurologic symptoms were excluded. Descriptive statistics were applied to analyze findings across the cohort. Results: A total of 22 clinical trials for metastatic RCC conducted from 2004-2017 required brain imaging at baseline, and a total of 535 pts were screened in this context. A total of 25/535 pts were found to have occult brain metastasis (4.67%), which was multi-focal in 10/25 (40%) and sub-cm in 15/25 (60%). For these 25 pts, the mean age at diagnosis was 56 years (38-77), and IMDC risk score at enrollment was: 1/24 favorable (4%), 21/24 intermediate (88%), and 2/24 poor-risk (8%) patients. 18/25 patients presented with de novo metastatic disease; 13/25 had received prior therapies; and 24/25 patients (96%) had > 2 additional non-CNS sites of metastatic disease at time of screening. 21/23 pts and 2/23 pts were then treated with radiation and surgical resection, respectively. Conclusions: This retrospective cohort study shows a 5% rate of occult CNS disease in asymptomatic patients with advanced RCC. These findings can inform current screening guidelines for full disease assessment in metastatic RCC patients.