Table 1.

Clinical backgrounds of the patients.

Total patients number	242
Gender	Male: 214, Female: 28
Age	55–92 (median: 77) y.o
Performance status (ECOG)	PS 0, 1, 2, 3, 4, NA * = 99, 114, 20, 2, 0, 7
Histology	squamous cell cancer: 92
	adenocarcinoma: 77
	unspecified non-small cell lung cancer: 18
	unproven: 55
Tumor size	3–50 mm (median: 27 mm)
T stage (7th UICC)	T1, T2 = 160, 82
Medical operability	operable:54, inoperable:175, NA *: 13
Smoking history	(+): 153, (−): 25, NA *: 64
Pulmonary emphysema	(+): 87, (−): 118, NA *: 37
Steroid administration before SBRT	(+): 20, (−): 174, NA *: 50
% vital capacity (% VC)	45.6–150.6% (mean: 91.9%)
FEV1.0% **	37.1–97.1% (mean: 67.9%)
SBRT dose	40–70 Gy in 4–10 fractions
V20 ***	1.1–21.7% (mean: 6.6%)

* NA: not assigned; ** FEV1.0%: percentage of predicted forced expiratory volume in one second; *** V20: rate of the volume irradiated with 20 Gy or more to the normal lung volume. (+): present; (−): absent.