Session Item

To investigate the effects of stereotactic body radiotherapy (SBRT) on local control or survival in oligometastatic renal cell cancer (RCC) patients in the era of immunotherapy.

A total of 33 patients and 63 lesions treated between March 2013 and October 2020. Twenty patients (60.6%) had de novo oligometastasis and 11 patients (33.4%) had oligoprogression during treatment or follow-up. Only patients with bone metastasis included this retrospective study with the aim of homogenous group. The diagnosis of metastasis was based on imaging studies. Histopathological verification was not mandatory. The local control (LC), overall survival (OS), and progression-free survival (PFS) rates were calculated using Kaplan-Meier analyses.

Median follow-up was 20 months. Fourteen patients (42.4%) were alive at last visit. Estimated median OS and PFS were 27.5 months (range, 14.6-40.4 months) and 19.4 months (range, 7.7-31 months), respectively. When we stratified patients by changing or keeping same systemic treatment there was no significant difference between two groups for OS (p=0.381) or PFS (p= 0.201).  1-year OS, PFS and local control (LC) rates were 69%, 38% and 82%, respectively. Clinical or radiological progression was observed in 8 irradiated lesions at first year. There was no grade 3 or more acute or late toxicity in the study cohort.

By providing excellent local control and low toxicity profile, SBRT is an effective treatment in oligometastatic RCC patients. The clinical outcomes seems similar for patients who continues to the same systemic chemotherapeutic or immunotherapy agent after local treatment of progressed lesion.