Table 1 Characteristics of the study population

Age, years (mean ± SD)

65.6 ± 11.3

-

63.2 ± 11.0

-

65.6 ± 12.8

-

66.0 ± 12.2

-

0.399

Sex (male)

46

37.4

18

39.1

43

34.1

29

55.8

0.057

Smoking

38

30.9

14

30.4

28

22.2

19

36.5

0.211

Family history of cancer

11

8.9

10

21.7

10

7.9

5

9.6

0.058

ECOG Performance Status score

0.006^*

 0

30

24.4

19

41.3

20

15.9

13

25.0

 1

70

56.9

24

52.2

65

51.6

29

55.8

 2

21

17.1

3

6.5

29

23.0

9

17.3

 3

2

1.6

0

0.0

11

8.7

1

1.9

 4

0

0.0

0

0.0

1

0.8

0

0.0

Stage of cancer

0.376

 IIIA

1

0.8

0

0.0

2

1.6

2

3.8

 IIIB

12

9.8

6

13.0

7

5.6

3

5.8

 IV

110

89.4

40

87.0

117

92.9

47

90.4

Histopathology

0.824

 Adenocarcinoma

117

95.1

45

97.8

121

96.0

49

94.2

 Squamous cell carcinoma

6

4.9

1

2.2

5

4.0

3

5.8

Number of metastases

0.590

 0

13

10.6

6

13.0

9

7.1

5

9.6

 1

56

45.5

20

43.5

50

39.7

21

40.4

 2

40

32.5

12

26.1

38

30.2

17

32.7

  ≥ 3

14

11.4

8

17.4

29

23.0

9

17.3

Brain metastases

40

32.5

12

26.1

60

47.6

21

40.4

0.025^*

EGFR mutation status

0.769

 Exon 19 deletion

48

39.0

17

37.0

56

44.4

21

40.4

 Exon 21 L858R

75

61.0

29

63.0

70

55.6

31

59.6

EGFR-TKI

0.919

 Erlotinib

65

52.8

26

56.5

67

53.2

30

57.7

 Gefitinib

58

47.2

20

43.5

59

46.8

22

42.3

Progressive disease

64

52.0

27

58.7

39

31.0

30

57.7

 < 0.001*

Skin rash

73

59.3

46

100.0

59

46.8

52

100.0

 < 0.001*

TC group

 Prophylaxis use

4

8.7

3

5.8

 Later use

42

91.3

49

94.2