Stereotactic body radiation therapy for inoperable localized kidney cancer

Purpose of the study: to evaluate the overall survival and local control in patients with inoperable kidney cancer treated with stereotactic body radiotherapy (SBRT). Material and Methods. From 2011 to 2021, 42 patients with histologically verified kidney cancer underwent SBRT to a total dose ranging from 30 to 45 Gr in 3 fractions using the CyberKnife robotic radiosurgical system. SBRT was performed for inoperable patients, taking into account various factors (age, severity of concomitant pathology, ASA IV physical status level), patients’ refusal of surgical treatment, and tumor size of ≤5.0 cm in diameter. SBRT was not performed for patients with tumor size of ≥5.0 cm in diameter, impaired renal function, generalization of cancer and decompensation of concomitant pathology. The median age of the patients was 67.9 years. 93 % of patients had stage I kidney cancer. The primary tumor was diagnosed in 37 cases, recurrence after previous surgical treatment in 6, including 1 patient with recurrence of cancer of both kidneys. The average tumor volume was 28.1 cm3. Results. The median overall survival (OS) was not reached due to the fact that the majority of patients (n=36) were alive at the time of the study. The 1-, 3- and 5-year OS rates were 94.1 %, 88.7 %, and 72.6 %, respectively. The 1-year local control rate was 93 %. At 3-6 months, 26.2 % of patients showed partial response, 66.8 % had stable disease and 7 % had disease progression (according to the RECIST 1.1 criteria). Renal toxicity occurred in 23.8 % of patients 3 months after radiation therapy; however, kidney function was restored in these patients within a year. Conclusion. SBRT has demonstrated high efficacy with minimal toxicity in the treatment of inoperable patients with kidney cancer.