Table 1 Clinical information of enrolled patients.

Cases

50

6

28

16

Gender

 Male

43

4

24

15

 Female

7

2

4

1

Median age (IQR, min–max)

65(11, 48–84)

63(13, 53–78)

65(9, 48–76)

66(16, 54–84)

Smoking

 Current

29

1

18

10

 Former

13

2

7

4

 Never

8

3

3

2

Drinking

 Current

36

3

21

12

 Former

7

1

4

2

 Never

7

2

3

2

Family history

 Yes

4

0

1

3

 No

46

6

27

13

Cancer location

 Upper

6

1

2

3

 Middle

33

4

19

10

 Down

11

1

7

3

Tumorsize (cm)

  ≥ 4

33

1

20

12

  < 4

17

5

8

4

Degree of differentiation

 High

13

1

10

2

 Middle

30

4

16

10

 Low

7

1

2

4

Lymph node metastasis

 Yes

21

0

7

14

 No

29

6

21

2