Safety and Efficacy of Robotic Radiosurgery for Visceral and Lymph Node Metastases of Renal Cell Carcinoma: A Retrospective, Single Center Analysis.

Despite rapid advances of systemic therapy options in renal cell carcinoma (RCC), local tumor or metastases treatment remains important in selected patients. Here, we assess the safety and efficacy of robotic radiosurgery (RRS) as an ablative therapy for visceral and lymph node metastases of RCC. Patients with histologically confirmed RCC and radiologically confirmed progression of visceral or lymph node metastases underwent RRS and were retrospectively analyzed. Overall survival and progression free survival were calculated by the Kaplan-Meier method and log-rank test. Sixty patients underwent RRS and were included in the analysis. Patients presented for RRS treatment with a median age at RRS treatment of 64 years (range 42-83), clear cell histology (88.3%) and favorable international metastatic renal cell carcinoma database (IMDC) risk score (58.3%). Treatment parameters differed for the number of fractions (median visceral metastases: 1, range 1-5; median lymph node metastases: 1, range 0-5; p = 0.003) and prescription dose (median visceral metastases 24 Gy, range 8-26; median lymph node metastases 18 Gy, range 7-26, p < 0.001). The median overall survival was 65.7 months (range: 2.9-108.6), the median progression free survival was 17.4 months (range: 2.7-70.0) and local tumor control was achieved in 96.7% of patients. Adverse events were limited to 8.3% of patients, with one grade 4 toxicity within 6 weeks after RRS therapy. RRS is a safe and effective treatment option in selected patients with metastatic RCC in a multimodal approach. Further research is warranted to confirm our findings prospectively.