Table 2. Univariate and multivariate analyses of overall survival for the SEER cohort.

Prognostic factor	Univariate analysis				Multivariate analysis
	P value	HR	95% CI		P value	HR	95% CI
Age, years	<0.001	0.5	0.484–0.517		<0.001	0.412	0.399–0.426
Sex	<0.001	0.948	0.921–0.976		<0.001	0.92	0.894–0.947
Location	<0.001	0.82	0.797–0.845		<0.001	0.871	0.846–0.897
pT stage	<0.001	2.647	2.542–2.756		<0.001	1.667	1.597–1.739
pN stage	<0.001	1.9	1.868–1.933		<0.001	1.458	1.430–1.488
pM stage	<0.001	3.989	3.873–4.109		<0.001	3.047	2.939–3.159
Perineural invasion	<0.001	1.128	1.112–1.145		<0.001	1.03	1.014–1.047
Tumor deposit	<0.001	2.685	2.594–2.780		<0.001	1.411	1.358–1.465

SEER, Surveillance Epidemiology and End Results; HR, hazard ratio; CI, confidence interval.