Table 3.

Summary of studies assessing stereotactic ablative radiotherapy (SABR) in localized primary renal cell carcinoma

Study	Design	Level of evidencea	Technique	Number of cases	Charlson Comorbidity Index	Tumor size(cm)	Complications	Follow-up (months)	Renal function decrease (%)	Residual disease (%)	Local recurrence (%)	Metastasis (%)	DFS (%)	OS (%)	CSS (%)
Siva [30]	Systematic review	2	SABR 3, 4, and 5 fraction approaches used. Mostly used: 40 Gy over 5 fractions.	126	NR	NR, but no size restrictions	Weighted rate of severe toxicity 3.8% Weighted rate of minor toxicity 21.4% Reported fatigue, nausea, radiation dermatitis and enteritis	Median/mean ranged from 9 to 57.7	NR	NR	Weighted local control 93.9% (range 84–100%) CT/MRI	NR	NR	NR	NR
Siva [31]	Prospective	3	Single 26 Gy (for tumor size ≤ 5 cm) versus 3 fractions of 14 Gy (for tumor size > 5 cm) SABR	37	76% of the patients had CCI ≥ 6	Median 4.8 (2.1–7.5)	78% Grade1–2 toxicity 3% Grade 3 toxicity Reported: fatigue chest wall pain, nausea	Median 24	11 mL/min eGFR in 1 year	NR	2 years freedom for local progression 100% CT/MRI	NR	2 years freedom from distant progression 89% (CI 78–100)	92% (2 years)	NR
Siva [32]	Multi-institutional pooled analysis	3	Both single-, and multi-fraction SABR included. Mean Gy 25 (14–70)	223	NR	Mean 4.36 (± 2,77)	35.6% Grade 1–2 toxicity 1.3% Grade 3–4 toxicity Reported: nausea, bowel toxicity	Median 30	Mean decrease in eGFR 5.5 ± 13.3 mL/min	NR	1.4% Local control: 97.8% at 2 years and 4 years CT/MRI	7.2%	PFS 77.4% (2 years) 65.4% (4 years)	82.1% (2 years) 70.7% (4 years)	95.7% (2 years) 91.9% (4 years)

Local recurrence was defined using Response Evaluation Criteria in Solid Tumors, version 1.0

Residual was not defined and not reported across all studies

ANS anesthesia, DFS disease-free survival, OS overall survival, CSS cancer-specific survival, NR not reported. CCI Charlson Comorbidity Index

^aLevel of evidence, Oxford 2011 [14]