Outcomes of High-Dose Stereotactic Ablative Radiotherapy to All/Multiple Sites for Oligometastatic Renal Cell Cancer Patients

Stereotactic ablative body radiotherapy (SABR) is one of the treatment options for oligometastatic renal cell carcinoma (RCC) but is limited by a lack of data to evaluate high-dose SABR to all/multiple sites. This study retrospectively investigated the efficacy and prognostic factors of high-dose SABR for oligometastatic RCC patients. Patients with oligometastatic RCC on systemic therapy were retrospectively collected. All patients were treated with SABR (40-50 Gy/5 fractions) for small tumors or partial-SABR (tumor center boosted with 6-8 Gy/3-5 fractions with 50-60 Gy/20-25 fractions to the whole tumor volume) for bulky tumors or tumors adjacent to critical organs. Progression-free survival (PFS) and overall survival (OS) were calculated. In total, 35 patients were enrolled, of which 88.5% had intermediate- or high-risk disease, with 60% on second- to fourth-line systemic therapy. The median follow-up time was 17 months. The median PFS and OS times were 11.3 and 29.7 months, respectively. Univariate analysis showed that an OS benefit was found in patients who received radiation before tyrosine kinase inhibitor (TKI) failure ( = 0.006) and where there was a short time interval (