Metastasis-directed stereotactic body radiotherapy for oligometastatic renal cell carcinoma: extent of tumor burden eradicated by radiotherapy.

We aimed to explore whether complete eradication of tumor burden with stereotactic body radiotherapy (SBRT) would affect the outcomes of oligometastatic renal cell carcinoma (RCC).

Patients diagnosed with extracranial oligometastatic RCC (no more than five metastases) between 2007 and 2019 were reviewed. Those without nephrectomy were excluded. SBRT to all, some and no lesions were defined as complete, incomplete, and no SBRT. Progression-free survival (PFS) and cancer-specific survival (CSS) were analyzed using Kaplan-Meier method, Cox regression model and the Fine and Gray method.

A total of 101 patients were included, 51.5% of whom had < 3 metastases. Forty (39.6%) patients received complete SBRT, and 61 (60.4%) received no or incomplete SBRT. The 1-year LC rate was 97.3%. The complete SBRT group had significantly longer PFS (26.0 vs 18.8 months; p = 0.043) and CSS (not reached vs. 55.3 months; p = 0.012) compared with the no or incomplete SBRT group. In multivariate analysis, ECOG 0-1 (HR 0.389, 95% CI 0.167-0.906, p = 0.029) and complete SBRT were prognostic factors for CSS (HR 0.307, 95% CI 0.108-0.876, p = 0.027). Complete SBRT was associated with improved CSS in the subgroups of patients with age < 55 years, ECOG 0-1, clear-cell histology, IMDC intermediate/poor risk, metachronous metastasis, and < 3 lesions.

Complete eradication of tumor burden with SBRT was associated with better survival in patients with oligometastatic RCC. The recommendation of SBRT to all lesions should be individualized.

World journal of urology. 2021 May 27 [Epub ahead of print]

Yang Liu, Wen Long, Zhiling Zhang, Zitong Zhang, Lixin Mai, Sijuan Huang, Hui Han, Fangjian Zhou, Pei Dong, Liru He

Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China., Department of Nuclear Medicine, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China., Department of Urology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China., Department of Urology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. ., Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. .