Table 1 Demographic and clinical characteristics of the patients in the baseline and longitudinal analyses. P-values of no significant difference analysis (p-value> 0.05) between the training and test set after two samples T-test for continuous variables, and Chi-square test for categorical variables. SD represents the standard deviation, and Q1 and Q3 represent the first and third quartiles, respectively

PFS, mean (SD)

9.0 (11.1)

9.3 (11.6)

7.6 (8.1)

0.242

11.1 (11.8)

11.6 (12.3)

9.0 (8.6)

0.147

OS, mean (SD)

13.3 (12.2)

13.3 (12.5)

13.5 (10.5)

0.903

16.0 (12.4)

16.0 (12.8)

15.7 (10.6)

0.889

Status

 Alive

107 (40.5%)

91 (41.2%)

16 (37.2%)

0.753

91 (45.5)

78 (46.7)

13 (39.4)

0.562

 Dead

157 (59.5%)

130 (58.8%)

27 (62.8%)

109 (54.5)

89 (53.3)

20 (60.6)

Response

 Non-responders

148 (56.1%)

124 (56.1%)

24 (55.8%)

1.000

90 (45.0%)

75 (44.9%)

15 (45.5%)

1.000

 Responders

116 (43.9%)

97 (43.9%)

19 (44.2%)

110 (55.0%)

92 (55.1%)

18 (54.5%)

Progression

 No progression

45 (17.0%)

40 (18.1%)

5 (11.6%)

0.417

42 (21.0%)

38 (22.8%)

4 (12.1%)

0.256

 Progression

219 (83.0%)

181 (81.9%)

38 (88.4%)

158 (79.0%)

129 (77.2%)

29 (87.9%)

 Age, median [Q1,Q3]

65.0 [59.0,71.0]

65.0 [58.0,71.0]

67.0 [60.5,72.5]

0.204

65.0 [58.0,70.2]

64.0 [57.0,70.0]

67.0 [60.0,72.0]

0.266

Sex

 Female

80 (30.3%)

66 (29.9%)

14 (32.6%)

0.865

58 (29.0%)

47 (28.1%)

11 (33.3%)

0.696

 Male

184 (69.7%)

155 (70.1%)

29 (67.4%)

142 (71.0%)

120 (71.9%)

22 (66.7%)

 IPA, mean (SD)

45.2 (33.4)

45.1 (33.8)

45.4 (31.5)

0.958

44.0 (34.1)

44.9 (34.6)

39.0 (31.2)

0.357

Smoking

 Current smoker

55 (21.0%)

50 (22.7%)

5 (11.9%)

0.258

39 (19.7%)

35 (21.1%)

4 (12.5%)

0.530

 Former smoker

180 (68.7%)

147 (66.8%)

33 (78.6%)

135 (68.2%)

111 (66.9%)

24 (75.0%)

 Non-smoker

27 (10.3%)

23 (10.5%)

4 (9.5%)

24 (12.1%)

20 (12.0%)

4 (12.5%)

Tumour histology

 Adenocarcinoma

203 (76.9%)

170 (76.9%)

33 (76.7%)

0.897

151 (75.5%)

126 (75.4%)

25 (75.8%)

0.896

 Epidermoid carcinoma

52 (19.7%)

43 (19.5%)

9 (20.9%)

40 (20.0%)

33 (19.8%)

7 (21.2%)

 Other

9 (3.4%)

8 (3.6%)

1 (2.3%)

9 (4.5%)

8 (4.8%)

1 (3.0%)

 PDL1, mean (SD)

0.4 (0.4)

0.4 (0.4)

0.4 (0.4)

0.876

0.4 (0.4)

0.4 (0.4)

0.3 (0.3)

0.194

Surgery

 No

227 (86.0%)

190 (86.0%)

37 (86.0%)

1.000

171 (85.5%)

142 (85.0%)

29 (87.9%)

0.792

 Yes

37 (14.0%)

31 (14.0%)

6 (14.0%)

29 (14.5%)

25 (15.0%)

4 (12.1%)

Treatment

 Combined immunological agents

39 (14.8%)

29 (13.1%)

10 (23.3%)

0.393

31 (15.5%)

24 (14.4%)

7 (21.2%)

0.276

 Immunotherapy + chemotherapy

50 (18.9%)

41 (18.6%)

9 (20.9%)

39 (19.5%)

30 (18.0%)

9 (27.3%)

 Immunotherapy + radiotherapy

17 (6.4%)

15 (6.8%)

2 (4.7%)

11 (5.5%)

11 (6.6%)

0 (0%)

 Monotherapy

154 (58.3%)

132 (59.7%)

22 (51.2%)

116 (58.0%)

99 (59.3%)

17 (51.5%)

 Other

4 (1.5%)

4 (1.8%)

0 (0%)

3 (1.5%)

3 (1.8%)

0 (0%)