Impact of stereotactic body radiotherapy vs palliative radiotherapy on oncologic outcomes of patients with metastatic kidney cancer concomitantly treated with immune checkpoint inhibitors: a preliminary, multicentre experience.

PURPOSE: To explore the benefit yielded by radiotherapy (RT), we report a series of metastatic renal cell carcinoma (RCC) patients treated with concomitant RT plus Nivolumab. METHODS/PATIENTS: Patients undergoing Nivolumab treatment plus concomitant RT (ablative or palliative) were included. RT was defined Ablative if >5 Gy/fraction were delivered. RESULTS: Ablative RT intent was the only independent predictor of both progression free and overall survival (HR 3.51, 95% CI 1.6-7.5, p = 0.0012 and HR 2.8, 95% CI 0.99-8.07, p = 0.05, respectively). CONCLUSION: Ablative RT may improve oncologic outcomes in selected patients with metastatic RCC treated with Nivolumab as compared to palliative RT.