Table 2.

Multivariable Cox regression analysis of factors associated with overall survival, disease-free survival and distant metastasis-free survival in the training and validation cohorts

	Training cohort (n=221)		Validation cohort (n=115)
	HR (95% CI)	P value	HR (95% CI)	P value
Variable
Overall survival
IS (3–6 vs 0–2)	0.34 (0.18 to 0.63)	0.001	0.42 (0.21 to 0.84)	0.014
TNM Stage (III–IV vs I–II)	3.49 (1.23 to 9.87)	0.019	10.7 (1.46 to 78.9)	0.020
EBV-DNA (>2000 vs ≤2000)	1.96 (1.01 to 3.78)	0.045	NA	NA
Disease-free survival
IS (3–6 vs 0–2)	0.44 (0.25 to 0.78)	0.005	0.37 (0.20 to 0.68)	0.001
TNM stage (III–IV vs I–II)	2.79 (1.18 to 6.62)	0.020	7.01 (1.68 to 29.2)	0.007
EBV-DNA (>2000 vs ≤2000)	2.13 (1.18 to 3.86)	0.013	NA	NA
Distant metastasis-free survival
IS (3–6 vs 0–2)	0.43 (0.21 to 0.87)	0.019	0.32 (0.14 to 0.75)	0.008
TNM stage (III–IV vs I–II)	3.52 (1.06 to 11.7)	0.040	7.68 (1.02 to 58.0)	0.048
EBV-DNA (>2000 vs ≤2000)	2.31 (1.08 to 4.93)	0.031	NA	NA

Bold values were considered significant

EBV, Epstein-Barr virus; IS, immune score; NA, not applicable; TNM, tumor-node-metastasis.