Table 1 Patient demographics, clinicopathological features, and epidermal growth factor receptor (EGFR) expression

Gender

0.130

  Male

176

77.0

45

80.4

131

70.1

  Female

67

23.0

11

19.6

56

29.9

Age (y)

0.675

  <40

12

4.9

4

7.17

8

4.3

  41 to 50

56

23.0

15

26.8

41

21.9

  51 to 60

101

41.6

21

37.5

80

42.8

  60 to 68

74

30.5

16

28.6

58

31.0

Length (cm)

0.730

  ≤5.0

130

53.5

32

57.1

98

52.4

  5.1 to 7.0

90

37.0

20

35.7

70

37.4

  >7.0

23

9.5

4

7.1

19

10.2

Tumor location

0.137

  Upper

33

13.6

5

5.9

28

15.0

  Middle

155

63.8

42

75.0

113

60.4

  Lower

55

22.6

9

16.1

46

24.6

Histological differentiation

0.607

  Well

93

38.3

21

37.5

72

38.5

  Moderate

124

51.0

27

48.2

97

51.9

  Poor

26

10.7

8

14.3

18

9.6

Tumor invasion

0.001

  T2

31

12.8

13

23.2

18

9.6

  T3

168

69.1

41

73.2

127

67.9

  T4

44

18.1

2

3.6

42

22.5

Lymph node status

0.002

  -

130

53.5

40

71.4

90

48.1

  +

113

46.5

16

28.6

97

51.9

Number of LNM

0.024

  1 to 2

65

57.5

8

50.0

57

58.8

  3 to 6

39

34.5

4

25.0

35

36.1

  ≥7

9

8.0

4

25.0

5

5.2

Pathological stage (UICC, sixth edition)

<0.0001

  IIA

110

41.3

39

69.6

71

38.0

  IIB

8

5.0

3

5.4

5

2.7

  III

125

51.4

14

25.0

111

59.4

Pathological stage (UICC, seventh edition)

0.002

  IB

23

9.5

10

17.9

13

7.0

  IIA

87

35.8

29

51.8

58

31.0

  IIB

5

2.1

1

1.8

4

2.1

  IIIA

68

28.0

7

12.5

61

32.6

  IIIB

28

11.5

4

7.1

24

12.8

  IIIC

32

13.2

5

8.9

27

14.4