Table 2 Clinical characteristics and treatment response of the study cohort

N (%)

58

30

28

Age (year) -mean ± SD

60.8 ± 10.8

59.2 ± 11

62.6 ± 10.4

0.2228

Age -n (%)

0.6431

 <65 years old

39 (67%)

21 (70%)

18 (64%)

 ≥65 years old

19 (33%)

9 (30%)

10 (36%)

Sex-n (%)

0.1949

 Female

38 (66%)

22 (73%)

16 (57%)

 Male

20 (34%)

8 (27%)

12 (43%)

Smoking history-n (%)

0.4214

 Never smoker

45 (78%)

22 (73%)

23 (82%)

 Ever smoker

13 (22%)

8 (27%)

5 (18%)

TTF-1 staining-n (%)

0.3411

 Negative

0 (0%)

0 (0%)

0 (0%)

 Positive

52 (90%)

28 (93%)

24 (86%)

 Not performed

6 (10%)

2 (7%)

4 (14%)

EGFR gene mutation site-n (%)

0.6671

 Exon18

3 (5%)

1 (3%)

2 (7%)

 Exon19

30 (52%)

16 (53%)

14 (50%)

 Exon19 + Exon21

1 (2%)

0 (0%)

1 (4%)

 Exon21

24 (41%)

13 (43%)

11 (39%)

Metastatic sites on initial diagnosis-n (%)

0.3083

 ≤1

23 (40%)

10 (33%)

13 (46%)

 ≥2

35 (60%)

20 (67%)

15 (54%)

Performance status while starting gefitinib-n (%)

0.1307

 ECOG ≤1

48 (83%)

27 (90%)

21 (75%)

 ECOG ≥2

10 (17%)

3 (10%)

7 (25%)

Progression-free survival of gefitinib (month) -median (IQR)

9.4 (6.2-13.8)

9.8 (6.1-12.5)

9.1 (7.6-16.1)

0.3466

Performance status while starting the second-line treatment-n (%)

0.8848

 ECOG ≤1

43 (74%)

22 (73%)

21 (75%)

 ECOG ≥2

15 (26%)

8 (27%)

7 (25%)

Progression-free survival of the second-line treatment (month) -median (IQR)

4.1 (2.7-6.1)

3.5 (2.0-4.7)

5.0 (2.9-7.0)

0.1836

Performance status while starting the third-line treatment-n (%)

0.0606

 ECOG ≤1

26 (45%)

17 (57%)

9 (32%)

 ECOG ≥2

32 (55%)

13 (43%)

19 (68%)

Initial treatment response to the third-line treatment-n (%)

0.0842

 Partial response

1 (2%)

1 (3%)

0 (0%)

 Stable disease

34 (59%)

21 (70%)

13 (46%)

 Progressive disease

23 (40%)

8 (27%)

15 (54%)

Initial disease control rate with the third-line treatment (%)

59%

73%

46%

0.0363