Table 3.

Univariate and Cox model analyses of the disease-free survival in the 674 patients.

Variables	Univariate	Cox model
	p	p	HR [95% CI]
Age (<40 vs. ≥40)	0.156
Sex (Male vs. female)	0.342
Smoker	<0.001	<0.001	1.461 [1.197–1.998]
Drinker	0.471
Primary site
Tongue + The mouth floor vs. others	<0.001	<0.001	2.476 [1.227–3.471]
Pathologic tumor stage
T3+T4 vs. T1+T2	<0.001	<0.001	3.446 [1.385–6.331]
Tumor differentiation
Moderate + poor vs. well	<0.001	<0.001	1.998 [1.264–3.558]
Perineural invasion	<0.001	<0.001	2.363 [1.277–4.338]
Lymphovascular invasion	<0.001	<0.001	2.255 [1.304–4.264]
Neck lymph node stage	<0.001
N0
N1		<0.001	1.685 [1.125–2.138]
N2		<0.001	2.453 [1.773–3.467]
N3		<0.001	3.007 [2.162–6.487]
Number of lymph node examined
<22 vs. ≥22	0.267
HPV positivity	0.993
p16 positivity	<0.001	<0.001	1.565 [1.183–2.021]
Positive margin	<0.001	<0.001	1.996 [1.317–2.778]
Number of positive lymph nodes	<0.001
0
1–2		<0.001	1.981 [1.241–2.525]
3–4		<0.001	3.126 [2.612–4.178]
≥5		<0.001	5.453 [4.431–8.465]