A comprehensive review of the role of immune checkpoint inhibitors in brain metastasis of renal cell carcinoma origin

The contribution of renal cell carcinoma (RCC) to brain metastases (BM) reaches 7-13%. These patients have limited survival with local control and targeted therapies. Immune checkpoint inhibitors (ICI) revolutionized the treatment landscape of RCC but commonly excluded BM patients from their pivotal trials. The daily clinical practice often imposes the use of ICI in RCC patients with BM in view of the promising survival times and durations of response. Only small prospective trials have included BM patients but rarely reported on the efficacy or safety of ICI in this subgroup. The available data is limited to small retrospective and prospective series that have shown comparable efficacy to that of the pivotal trials. In this review, we will discuss the biological rationale and potential concerns for the use of ICI in BM RCC. Furthermore, we will summarize BM subgroup data from the prospective and retrospective series of ICI in RCC as well as the use of cranial radiation and ICI.