Assistant Professor Klinikum der Universität München, Department of Urology Munich, Germany
Background: Robotic radiosurgery (RRS) as a variant of stereotactic radiotherapy has attracted interest in renal cell carcinoma (RCC). However, the safety and efficacy as well as survival outcomes of patients with metastatic RCC are unclear.
Methods: A retrospective single-center analysis was performed. Patients underwent RRS for histologically confirmed metastatic RCC. Inclusion criteria for this study were RRS treated metastases of lungs, visceral and lymph node metastases. Indications included oligometastatic disease defined as five or less lesions as well as oligoprogressive disease or limited systemic treatment options. A standardized follow-up was performed after three months and according to the EAU guidelines. The Common Terminology Criteria for Adverse Events (CTCAE) guidelines were used for adverse event assessment. Kaplan-Meier-Method was used to calculate overall survival (OS), progression free survival (PFS) and local recurrence free survival (LRFS).
Results: 50 patients with lung metastases, 44 with visceral metastases and 16 with lymph node metastases met the inclusion criteria and received RRS treatment. Median age of patients at the time of RRS was 64 (range 42 – 92) years with 102 patients presenting with clear cell RCC, one with papillary type 1, 3 with papillary type 2, 3 with chromophobe histology and one with a TFE-3 translocation. Median PFS is 13 (1-93) months for patients with lung metastases, 17.2 (2.7–70.0) months for visceral metastases and 22.5 (2.8–45.6) months for lymph node metastases. Local recurrence was observed in three patients. Median OS for patients with lung metastases is 35 (1-117) months, for patients with visceral metastases 65.7 (2.9–108.6) months and with lymph node metastases 36.8 (10.0–48.2) months. AE were limited to grade 1 or 2 with the exception of one patient suffering from grade 4 stroke and thrombosis. The most frequent AE was fatigue (n=8), followed by pneumonitis (n=2) in the lung metastases group.
Conclusion: RRS was effective and safe in our highly selected patient cohort. Long-term outcomes seem favorable. Further studies should focus on the precise effect of RRS in oligoprogressive disease under systemic therapy.