Stereotactic body radiotherapy plus sunitinib vs. sunitinib alone in treatment-naive oligometastatic renal cell carcinoma: A phase 2 clinical trial.

Comparative data on stereotactic body radiotherapy (SBRT) in oligometastatic renal cell carcinoma (RCC) is lacking. This single-center, phase 2 non-randomized controlled trial enrolls patients with treatment-naive oligometastatic RCC. Patients choose to receive sunitinib alone (control arm, n = 24) or plus SBRT (SBRT arm, n = 24). The primary endpoint, objective response rate (83.3% vs. 29.2%; p < 0.001), is higher in the SBRT arm. With a median follow-up of 40.6 months, the 1-year local control rate is 91.5%. Progression-free survival (PFS) is significantly longer in the SBRT arm (17.3 vs. 6.3 months; p = 0.036). Post hoc multivariable analysis shows that SBRT significantly prolongs PFS (hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.21-0.84; p = 0.015). Grade 3 toxicities are similar (54.2% vs. 50.0%, p = 0.773). The SBRT arm shows a trend toward better quality of life. These suggest potential benefit of SBRT in oligometastatic RCC, requiring further validation by phase 3 trials. The trial is registered at Chictr.org.cn (ChiCTR1800017136).