Table 2.

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.