Clinical efficacy of stereotactic ablative radiotherapy for lung metastases arising from colorectal cancer

Table 2 Univariate analysis of prognostic factors associated with the local control and overall survival

Factors	n	3-year LC (%)	p value	n	3-year OS (%)	p value
Age (years)			0.44			0.80
<65	35	73.3		24	58.3
≥65	44	67.5		26	69.2
ECOG performance score			0.43			0.47
0–1	66	71.6		40	70.0
2	12	62.3		9	33.3
Stage of the primary tumor			0.98			0.43
Stage 1–2	20	69.4		13	61.5
Stage 3–4	57	70.9		35	65.7
Timing of SABR			0.04			0.42
First pulmonary metastasis	51	62.6		33	72.7
Second or third	28	90.9		17	47.1
Pre-SABR CEA level			<0.01			0.40
≤6	62	78.1		39	64.1
>6	10	0		6	66.7
GTV			0.01			0.02
≤1.5 mL	41	88.5		25	68.0
>1.5 mL	38	50.1		25	60.0
Radiation dose			0.14			0.12
≤48 Gy	56	64.6		33	54.5
60 Gy	23	84.0		17	82.4
LC			-			0.06
Yes	-	-		39	66.7
No	-	-		11	54.5

LC local control, OS overall survival, ECOG Eastern Cooperative Oncology Group, SABR stereotactic ablative body radiotherapy, CEA carcinoembryonic antigen, GTV gross tumor volume