Table 1 Patient characteristics (N = 205)

Age(years)

62.2 ± 9.1

63.4 ± 9.6

t = 0.914

0.362

Gender

Male

51

69

\(\:{{\upchi\:}}^{2}\)=0.958

0.382

Female

42

43

Smoking history

46

60

\(\:{{\upchi\:}}^{2}\)=0.344

0.558

Comorbidities

Diabetes

10

12

\(\:{{\upchi\:}}^{2}\)=0

0.993

Hypertension

19

24

\(\:{{\upchi\:}}^{2}\)=0.031

0.861

Coronary heart disease

5

7

\(\:{{\upchi\:}}^{2}\)=0.071

0.79

Tumor location

Upper Thoracic

18

28

\(\:{{\upchi\:}}^{2}\)=0.945

0.623

Middle Thoracic

54

61

Lower Thoracic

21

23

Pathological stage

(TNM stage)

IA

8

11

Z = 0.562

0.574

IB

15

12

IIA

23

38

IIB

20

27

IIIA

17

14

IIIB

10

10