Table 1 Demographics and clinicopathologic characteristics of the training and external validation cohor
| Â | Training cohort | Internal validation cohort | External validation cohort |
|---|---|---|---|
Characteristics | (N = 18,805,n(%) | (N = 8136), n(%) | (N = 505), n(%) |
Age | |||
 <50 | 1003 (5.33) | 399 (4.90) | 119 (23.56) |
 50 ~ 59 | 3252 (17.29) | 1480 (18.19) | 129 (25.54) |
 60 ~ 69 | 6789 (36.10) | 2857 (35.12) | 166 (32.87) |
 ≥ 70 | 7761 (41.27) | 3400 (41.79) | 91 (18.02) |
Sex | |||
 Female | 10505 (55.86) | 4454 (54.74) | 327 (64.75) |
 Male | 8300 (44.14) | 3682 (45.26) | 178 (35.25) |
PrimarySite | |||
 Upper | 10973 (58.35) | 4737 (58.22) | 308 (60.99) |
 Middle | 1159 (6.16) | 489 (6.01) | 44 (8.71) |
 Lower | 6172 (32.82) | 2710 (33.31) | 140 (27.72) |
 Other | 501 (2.66) | 200 (2.46) | 13 (2.57) |
TumorType | |||
 Adenocarcinoma | 12034 (63.99) | 5175 (63.61) | 473 (93.66) |
 Squamous cell carcinoma | 4482 (23.83) | 1957 (24.05) | 25 (4.95) |
 Adenosquamous carcinoma | 418 (2.22) | 200 (2.46) | 1 (0.20) |
 Large cell carcinoma | 374 (1.99) | 161 (1.98) | 3 (0.59) |
 Others | 1497 (7.96) | 643 (7.90) | 3 (0.59) |
Grade | |||
 Unknown | 1536 (8.17) | 652 (8.01) | 4 (0.79) |
 Grade I | 3861 (20.53) | 1664 (20.45) | 307 (60.79) |
 Grade II | 7880 (41.90) | 3468 (42.63) | 97 (19.21) |
 Grade III | 5288 (28.12) | 2266 (27.85) | 60 (11.88) |
 Grade IV | 240 (1.28) | 86 (1.06) | 37 (7.33) |
Laterality | |||
 Left | 7800 (41.48) | 3280 (40.31) | 213 (42.18) |
 Right | 11005 (58.52) | 4856 (59.69) | 292 (57.82) |
Stage | |||
 IA | 8999 (47.85) | 3932 (48.33) | 445 (88.12) |
 IB | 5053 (26.87) | 2173 (26.71) | 42 (8.32) |
 IIA | 2524 (13.42) | 1119 (13.75) | 10 (1.98) |
 IIB | 2229 (11.85) | 912 (11.21) | 8 (1.58) |
T | |||
 T1 | 9696 (51.56) | 4234 (52.04) | 416 (82.38) |
 T2 | 7185 (38.21) | 3126 (38.42) | 61 (12.08) |
 T3 | 1924 (10.23) | 776 (9.54) | 28 (5.54) |
N | |||
 N0 | 16822 (89.45) | 7249 (89.10) | 490 (97.03) |
 N1 | 1983 (10.55) | 887 (10.90) | 15 (2.97) |
Surgery | |||
 Sub-lobectomy | 3375 (17.95) | 1467 (18.03) | 358 (70.89) |
 Lobectomy | 14256 (75.81) | 6151 (75.60) | 145 (28.71) |
 Pneumonectomy | 1110 (5.90) | 479 (5.89) | 1 (0.20) |
 Palliative | 64 (0.34) | 39 (0.48) | 1 (0.20) |
Chemotherapy | |||
 No/Unknow | 15519 (82.53) | 6692 (82.25) | 464 (91.88) |
 Yes | 3286 (17.47) | 1444 (17.75) | 41 (8.12) |
Nodes | |||
 0 | 1663 (8.84) | 747 (9.18) | 97 (19.21) |
 1 ~ 9 | 9743 (51.81) | 4198 (51.60) | 206 (40.79) |
 10 ~ 19 | 5380 (28.61) | 2287 (28.11) | 140 (27.72) |
 20 ~ 29 | 1479 (7.86) | 609 (7.49) | 49 (9.70) |
 ≥ 30 | 540 (2.87) | 295 (3.63) | 13 (2.57) |
Positive | |||
 No/Unknow | 16876 (89.74) | 7275 (89.42) | 493 (97.62) |
 Yes | 1929 (10.26) | 861 (10.58) | 12 (2.38) |
TumorSize | |||
 ≤ 9 mm | 791 (4.21) | 336 (4.13) | 233 (46.14) |
 10 ~ 19 mm | 5707 (30.35) | 2490 (30.60) | 182 (36.04) |
 20 ~ 29 mm | 5342 (28.41) | 2294 (28.20) | 51 (10.10) |
 ≥ 30 mm | 6965 (37.04) | 3016 (37.07) | 39 (7.72) |
Number | |||
 1 | 16,053 (85.37) | 6968 (85.64) | 467 (92.48) |
 ≥ 2 | 2752 (14.63) | 1168 (14.36) | 38 (7.52) |