Table 1 Distributions of demographic and clinicopathological variables of patients with resectable LUAD in the discovery set and the three external validation sets
Variable | Discovery set N (%) | Validation set V1 N (%) | Validation set V2 N (%) | Validation set V3 N (%) | P |
|---|---|---|---|---|---|
Number of patients | 31/111* | 30/115* | 37/116* | 80/246* | Â |
Age |  |  |  |  |  < 0.0001# |
 < 65 years | 41(36.9) | 19(16.5) | 78(67.2) | 124(50.4) |  |
  ≥ 65 years | 70(63.1) | 96(83.5) | 38(32.8) | 122(49.6) |  |
Sex | Â | Â | Â | Â | 0.1603# |
 Male | 58(52.3) | 58(50.4) | 66(56.9) | 110(44.7) |  |
 Female | 53(47.7) | 57(49.6) | 50(43.1) | 136(55.3) |  |
Smoking Status |  |  |  |  |  < 0.0001†|
 Ever | 32(28.8) | 41(35.7) | 56(48.3) | 213(86.6) |  |
 Never | 79(71.2) | 74(64.3) | 60(51.7) | 30(12.2) |  |
 Unknown | 0(0.0) | 0(0.0) | 0(0.0) | 3(1.2) |  |
Tumor site |  |  |  |  | 0.2230†|
 Upper/Middle | 72(64.9) | 65(56.5) | 64(55.2) | 160(65.0) |  |
 Lower | 39(35.1) | 50(43.5) | 52(44.8) | 84(34.2) |  |
 Unknown | 0(0.0) | 0(0.0) | 0(0.0) | 2(0.8) |  |
Treatment |  |  |  |  |  < 0.0001†|
 Surg. Only | 76(68.5) | 56(48.7) | 55(47.4) | 139(56.5) |  |
 Surg. + Chemo | 35(31.5) | 59(51.3) | 61(52.6) | 87(35.4) |  |
 Unknown | 0(0.0) | 0(0.0) | 0(0.0) | 20(8.1) |  |
Differentiation |  |  |  |  |  < 0.0001# |
 G1/G2 | 86(77.5) | 60(52.2) | 70(60.3) | NA |  |
 G3/G4 | 22(19.8) | 40(34.8) | 46(39.7) | NA |  |
 Unknown | 3(2.7) | 15(13.0) | 0(0.0) | NA |  |
TNM stage |  |  |  |  |  < 0.0001# |
 I | 79(71.2) | 70(60.9) | 49(42.2) | 145(58.9) |  |
 II | 15(13.5) | 17(14.8) | 38(32.8) | 65(26.4) |  |
 III | 17(15.3) | 28(24.3) | 29(25.0) | 36(14.6) |  |