Table 1.

Variables assignment and analysis results of Cox’s regression models for NPC

Analysis type	Factor	Grouping and assignment	Available cases		P-value	HR	95.0% CI for HRs
			Death	Censored			Lower	Upper
Univariate	Age	Continuous variable	71	299	.002	1.03	1.01	1.05
	Gender	1 = “male”; 2 = “female”			.017	.36	.16	.83
	Clinical stage	1 = “I”; 2 = “II”; 3 = “III”; 4 = “IV”	71	295	.001	3.14	1.56	6.35
	EBV-DNA	Continuous variable	64	251	.001	1.00	1.00	1.00
	CTCs	Continuous variable	71	299	.000	1.00	1.00	1.00
Multivariate	Age	Continuous variable	64	248	.003	1.03	1.01	1.06
	Gender	1 = “male”; 2 = “female”			.118	.51	.22	1.19
	Clinical stage	1 = “I”; 2 = “II”; 3 = “III”; 4 = “IV”			.002	3.14	1.54	6.41
	EBV-DNA	Continuous variable			.058	1.00	1.00	1.00
	CTCs	Continuous variable			.001	1.00	1.00	1.00