Table 1 Baseline clinical characteristics of the training cohort and the validation cohorts

Age (years), n (%)

0.931

 <60

72 (44.7%)

29 (42%)

18 (43.9%)

 ≥60

89 (55.3%)

40 (58%)

23 (56.1%)

Gender, n (%)

0.181

 Male

156 (96.9%)

66 (95.7%)

37 (90.2%)

 Female

5 (3.1%)

3 (4.3%)

4 (9.8%)

BMI, mean ± sd

22.403 ± 3.026

22.649 ± 3.181

22.356 ± 2.998

0.833

Smoking, n (%)

0.736

 Never

45 (28%)

18 (26.1%)

9 (22%)

 Former or current

116 (72%)

51 (73.9%)

32 (78%)

Drinking, n (%)

0.968

 Never

51 (31.7%)

23 (33.3%)

13 (31.7%)

 Former or current

110 (68.3%)

46 (66.7%)

28 (68.3%)

cT stage, n (%)

0.966

 T2

47 (29.2%)

19 (27.5%)

12 (29.3%)

 T3

114 (70.8%)

50 (72.5%)

29 (70.7%)

cN stage, n (%)

0.579

 N0

14 (8.7%)

8 (11.6%)

1 (2.4%)

 N1

96 (59.6%)

41 (59.4%)

26 (63.4%)

 N2

51 (31.7%)

20 (29%)

14 (34.1%)

cTNM stage, n (%)

0.658

 II

26 (16.1%)

13 (18.8%)

9 (22%)

 III

135 (83.9%)

56 (81.2%)

32 (78%)

Tumor Location, n (%)

0.285

 Upper

7 (4.3%)

7 (10.1%)

3 (7.3%)

 Middle

81 (50.3%)

35 (50.7%)

25 (61%)

 Lower

73 (45.3%)

27 (39.1%)

13 (31.7%)

Tumor length (cm), n (%)

0.097

 <5

85 (52.8%)

47 (68.1%)

24 (58.5%)

 ≥5

76 (47.2%)

22 (31.9%)

17 (41.5%)

Immune checkpoint inhibitors

0.257

 Camrelizumab

146 (90.7%)

60 (87.0%)

33 (80.4%)

 Tirelizumab

9 (5.6%)

7 (10.1%)

4 (9.8%)

 Sintilimab

6 (3.7%)

2 (2.9%)

4 (9.8%)

Cycles, n (%)

0.748

 2–3

125 (77.6%)

55 (79.7%)

34 (82.9%)

 4

36 (22.4%)

14 (20.3%)

7 (17.1%)

SCC (ng/mL), mean ± sd

2.441 ± 6.484

1.626 ± 1.961

1.736 ± 2.431

0.482

pCR, n (%)

0.995

 No

115 (71.4%)

49 (71.1%)

29 (70.7%)

 Yes

46 (28.6%)

20 (28.9%)

12 (29.3%)