Table 1 Patient and tumor characteristics

Age (years), median (range)

83 (80.0–94.8)

Sex (n), male/female

45/19

Follow-up (months), median (range)

39 (3.5–95.7)

BMI (kg/m²), median (range)

22.8 (16.7–29.4)

BMI distribution (n), < 18.5/18.5–25.0/ > 25 kg/m²

5/48/11

ECOG PS (n), 0/1/2/3

28/19/11/6

Operability (n), yes/no

16/48

GOLD stage (n), normal/I/II/III†

24/18/13/4

FEV1.0 (L), median (range) †

1.6 (0.7–2.7)

History of lung operation (n), yes/no

14/50

Charlson Comorbidity Index (n), 2/3/4/5/6/7/9

10/28/12/7/3/2/2

T stage (n), Tis/T1mi/T1a/T1b/T1c/T2a/T2b

2/2/5/26/17/10/3

Maximum tumor diameter (cm), median (range)

2.1 (0.8–4.1)

ITV (mL), median (range)

10.2 (1.1–51.8)

PTV (mL), median (range)

32.4 (9.6–110.6)

Histology (n)

 Adenocarcinoma

43

 Squamous cell carcinoma

19

 Unclassified NSCLC

3

Tumor opacity (n), pure GGN/part solid GGN/solid

2/18/45

Location (n), central/peripheral

1/64

Location (n), left/right

24/41

Location (n), upper lobe/middle lobe/lower lobe

37/1/27

Prescribed dose (n)

 48 Gy (isocenter)

41

 60 Gy (isocenter)

6

 48 Gy (D95)

18