When surgery is not an option in renal cell carcinoma: The evolving role of stereotactic body radiation therapy

Historically, radiation therapy has played a limited role in the management of renal cell carcinoma because early studies showed that it had no benefit in the neoadjuvant or adjuvant settings. Thus, radiation has typically been employed for only palliation of metastatic sites. As the ability to deliver conformal high-dose-perfraction radiation became available, studies began to show excellent local control when treating oligometastatic sites of renal cell carcinoma with stereotactic body radiation therapy (SBRT). Recently, SBRT has been studied in the management of the primary tumor in nonsurgical patients with localized renal cell carcinoma. Excellent local control rates and low rates of treatment-related toxicity were reported with single-fraction (26 Gy) and multi-fraction (36 to 45 Gy in 3 fractions or 40 to 50 Gy in 5 fractions) regimens. While the evidence to date is limited by small cohort sizes and variability in treatment approaches, the reported outcomes are promising. Ongoing studies will continue to define how renal SBRT fits into the management of patients who are not eligible for surgery.