Table 3.

Multivariable Cox models for PSM dataset (n = 872)

	PFS		OS		LRRFS		DMFS
	HR (95% CI)	p value	HR (95% CI)	p value	HR (95% CI)	p value	HR (95% CI)	p value
Age		NS		0.004		NS		NS
≤ 45			Reference
> 45			3.16(1.44–6.92)
N stage		< 0.001		0.002		< 0.001		NS
N0	Reference		Reference		Reference
N1	2.44(1.48–4.00)		4.14(1.67–10.16)		3.50(1.73–7.07)
EBV DNA		0.042		NS				< 0.001
< 4000	Reference						Reference
≥ 4000	1.74(1.01–2.97)						3.55(1.84–6.85)
PET/CT obtained		0.262		0.196		0.526		0.182
Yes	Reference		Reference		Reference		Reference
No	0.72(0.40–1.28)		0.56(0.23–1.35)		0.79(0.38–1.64)		0.49(0.17–1.40)

p value < 0.05 indicates a statistically significant difference

Abbreviations: PFS, progression-free survival; OS, overall survival; LRRFS, locoregional relapse-free survival; DMFS, distant metastasis-free survival