Table 1 Clinical characteristics of the patients in the primary and external validation sets
|  | Primary training (n = 105) |  | Internal validation (n = 54) |  | External validation (n = 24) |  | |||
|---|---|---|---|---|---|---|---|---|---|
Characteristic | EGFR mutant (n = 69) | EGFR wild-type (n = 36) | p | EGFR mutant (n = 35) | EGFR wild-type (n = 19) | p | EGFR mutant (n = 17) | EGFR wild-type (n = 7) | p |
Age (Mean ± SD) | 58.71 ± 9.34 | 57.14 ± 11.28 | 0.448 | 58.14 ± 12.11 | 59.21 ± 8.95 | 0.738 | 59.06 ± 7.78 | 60.14 ± 5.61 | 0.742 |
Sex | Â | Â | 0.080 | Â | Â | 0.799 | Â | Â | 0.202 |
 Male | 26 (37.7%) | 20 (55.6%) |  | 19 (54.3%) | 11 (57.9%) |  | 5 (29.4%) | 4 (57.1%) |  |
 Female | 43 (62.3%) | 16 (44.4) |  | 16 (45.7%) | 8 (42.1%) |  | 12 (70.6%) | 3 (42.9%) |  |
Smoking status | Â | Â | 0.063 | Â | Â | 0.532 | Â | Â | 0.344 |
 Yes | 20 (29.0%) | 17 (47.25) |  | 10 (28.6%) | 7 (36.8%) |  | 4 (23.5%) | 3 (42.9%) |  |
 No | 49 (71.0%) | 19 (52.8%) |  | 25 (71.4%) | 12 (63.2%) |  | 13 (76.5%) | 4 (57.1%) |  |
PS Score | Â | Â | 0.553 | Â | Â | 0.645 | Â | Â | 0.551 |
 0 | 8 (11.6%) | 2 (5.6%) |  | 3 (8.5%) | 1 (5.3%) |  | 3 (17.6%) | 3 (42.9%) |  |
  1 | 48 (69.6%) | 29 (80.6%) |  | 22 (62.9%) | 15 (78.9%) |  | 11 (64.7%) | 3 (42.9%) |  |
  2 | 10 (14.5%) | 3 (8.3%) |  | 8 (22.9%) | 2 (10.5%) |  | 2 (11.8%) | 1 (14.2%) |  |
  3 | 3 (4.3%) | 2 (5.6%) |  | 2 (5.7%) | 1 (5.3%) |  | 1 (5.9%) | 0 (0.0%) |  |
CEA (Mean ± SD) | 127.01 ± 225.86 | 118.40 ± 184.17 | 0.364 | 84.4 ± 178.92 | 107.57 ± 276.57 | 0.738 | 102 ± 132.94 | 81.22 ± 124.14 | 0.187 |
CYFRA (Mean ± SD) | 8.66 ± 13.51 | 10.51 ± 10.12 | 0.473 | 9.8 ± 13.09 | 12.19 ± 10.34 | 0.140 | 14.18 ± 19.25 | 6.61 ± 3.19 | 0.852 |
NSE (Mean ± SD) | 21.01 ± 14.59 | 21.47 ± 11.03 | 0.787 | 21.44 ± 16.73 | 15.22 ± 6.71 | 0.258 | 28.11 ± 28.34 | 18.15 ± 5.99 | 0.710 |