Table 3.

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)
Variable	HR (95% CI)	P		HR (95% CI)	P
overall survival
Immune Hotspot (high vs low)	0.40 (0.21–0.76)	0.005		0.42 (0.21–0.84)	0.015
TNM Stage (III–IV vs. I–II)	3.25 (1.15–9.20)	0.026		10.8 (1.46–79.2)	0.020
EBV-DNA (> 2000 vs.≤ 2000)	2.12 (1.09–4.09)	0.026		NA	NA
disease-free survival
Immune Hotspot (high vs low)	0.42 (0.24–0.74)	0.003		0.52 (0.29–0.94)	0.031
TNM Stage (III–IV vs. I–II)	2.63 (1.11–6.21)	0.028		7.20 (1.73–29.9)	0.007
EBV-DNA (> 2000 vs.≤ 2000)	2.30 (1.27–4.16)	0.006		NA	NA
distant metastasis-free survival
Immune Hotspot (high vs low)	0.39 (0.19–0.80)	0.01		0.37 (0.16–0.86)	0.021
TNM Stage (III–IV vs. I–II)	3.32 (1.00–11.0)	0.049		7.71 (1.03–57.9)	0.047
EBV-DNA (> 2000 vs.≤ 2000)	2.48 (1.16–5.29)	0.019		NA	NA

Abbreviations: HR, hazard ratio; CI, confidence interval; TNM, Tumor-node-metastasis; EBV-DNA, Epstein-Barr virus DNA.