Stereotactic ablative radiotherapy (SABR) is effective and well-tolerated in people with primary renal cell carcinoma, according to an analysis involving 223 individuals. Participants were from 5 countries, including the US, and received either single fraction (n=118) or multifraction (n=105) SABR. Investigators looked at toxicities and survival outcomes. Among the results:

• 35% had grade 1 or 2 toxicities; 2% had grade 3 or 4 toxicities.
• At both 2 and 4 years, 98% experienced local control
• 2-year cancer-free and progression-free survival rates were 96% and 77%, respectively.
• These rates at 4 years were 92%, and 65%, respectively.
• Patients whose tumors had a larger maximum dimension experienced poorer progression-free and cancer-specific survival (16% and 28%, respectively).
• Those receiving multifraction SABR were also more likely to experience poorer progression-free and cancer-specific survival (13% and 33%, respectively).
• Local failure rates were similar in the single fraction and multifraction cohorts (1 and 2 patients, respectively).