Unique behavior of brain metastases during the treatment of nivolumab for metastatic renal cell carcinoma

Brain metastases (BM) is one of the most unfavorable metastatic outcomes occurring in patients with renal cell carcinoma, and the overall survival (OS) of the patients with BM is approximately 1 year even after the advent of targeted therapy (1,2). BM may also cause neurological symptoms, which significantly reduces the patients’ quality of life. Thus, the control of BM is very important for the management of patients with metastatic renal cell carcinoma (mRCC).