Multivariable Cox regression analysis of prognostic factors in the training cohort and validation cohort
| HR* (95% CI) | P value | |
| Distant metastasis-free survival | ||
| Training cohort (n=194) | ||
| HGB (≥130 vs <130 g/L) | 0.335 (0.126 to 0.890) | 0.028 |
| N category (2–3 vs 0–1) | 2.522 (1.086 to 5.857) | 0.031 |
| Immune signature (high vs low) | 6.295 (2.886 to 13.729) | <0.001 |
| Validation cohort (n=304) | ||
| Age (≥45 years vs <45 years) | 3.003 (1.355 to 6.654) | 0.007 |
| N stage (N2–3 vs N0–1) | 3.461 (1.501 to 7.979) | 0.004 |
| Immune signature (high vs low) | 4.297 (2.182 to 8.461) | <0.001 |
| Progression-free survival | ||
| Training cohort (n=194) | ||
| N category (2–3 vs 0–1) | 2.136 (1.107 to 4.118) | 0.024 |
| Immune signature (high vs low) | 2.775 (1.484 to 5.189) | 0.001 |
| Validation cohort (n=304) | ||
| HGB (≥130 vs <130 g/L) | 0.535 (0.325 to 0.878) | 0.013 |
| Age (≥45 years vs <45 years) | 2.018 (1.194 to 3.411) | 0.009 |
| N stage (N2–3 vs N0–1) | 1.713 (1.028 to 2.854) | 0.045 |
| Immune signature (high vs low) | 2.115 (1.289 to 3.469) | 0.003 |
HRs and p values were calculated using an adjusted multivariate Cox proportional hazards regression model, immune signature (high risk vs low risk), gender (male vs female), age (≥45 years vs <45 years), T stage (T3–4 vs T1–2), N stage (N2–3 vs N0–1), overall stage (I–III vs IV), ECOG (0 vs 1 vs 2), LDH (≥245 vs <245 U/L), CRP (≥3 vs <3 mg/L), HGB (≥130 vs <130 g/L), and BMI (≥23 vs <23 kg/m²) were included as covariates. Variables were selected with the backward stepwise approach, and the p value threshold was 0.1 (p>0.1) for removing insignificant variables from the model. Only variables significantly associated with survival were presented, and marginally significant variables (0.05<p<0.1) were remained in the final Cox model but not presented in the table.
BMI, body mass index; CRP, serum C reactive protein; ECOG, Eastern Cooperative Oncology Group; HGB, hemoglobin; LDH, serum lactate dehydrogenase.