Table 2. Stratified survival analysis according to major clinical factors of three cohorts.
| Variable | Discovery cohort | Validation-1 cohort | Validation-2 cohort | ||||||||||
| Low risk | High risk | P-value | HR(95%CI) | Low risk | High risk | P-value | HR(95%CI) | Low risk | High risk | P-value | HR(95%CI) | ||
| AJCC stage | |||||||||||||
| I/IIA | 16 | 10 | 0.131 | 2.09(0.69-6.33) | 32 | 17 | 0.026 | 2.66(0.94-7.51) | 4 | 10 | 0.125 | 4.33(1.15-16.27) | |
| IIB/III/IV | 30 | 41 | 0.001 | 2.41(1.36-4.27) | 53 | 72 | 0.064 | 1.57(0.99-2.48) | 29 | 23 | 0.020 | 2.00(1.04-3.85) | |
| T stage | |||||||||||||
| T1/T2 | 9 | 9 | 0.086 | 2.31(0.73-7.32) | 19 | 12 | 0.028 | 3.58(1.02-12.59) | NA | NA | NA | NA | |
| T3/T4 | 39 | 41 | 0.0006 | 2.53(1.43-4.46) | 66 | 78 | 0.014 | 1.73(1.12-2.68) | NA | NA | NA | NA | |
| N stage | |||||||||||||
| N- | 18 | 10 | 0.135 | 2.01(0.68-5.95) | 30 | 19 | 0.017 | 2.86(1.05-7.81) | 7 | 13 | 0.467 | 1.53(0.52-4.50) | |
| N+ | 32 | 41 | 0.001 | 2.48(1.41-4.36) | 46 | 77 | 0.041 | 1.69(1.06-2.70) | 26 | 20 | 0.008 | 2.30(1.14-4.60) | |
| Histological grade | |||||||||||||
| G1/G2 | NA | NA | NA | NA | 66 | 59 | 0.0003 | 2.53(1.51-4.24) | 25 | 9 | 0.674 | 1.20(0.50-2.88) | |
| G3/G4 | NA | NA | NA | NA | 19 | 31 | 0.447 | 1.33(0.65-2.71) | 7 | 24 | 0.399 | 1.50(0.63-3.60) | |
Abbreviation: HR, hazard ratio; CI, confidence interval; AJCC, American Joint Committee on Cancer; NA, not available