Table 4.

Results of univariate analysis of selected prognostic factors for overall survival.

Characteristics	Number of cases	Number of deaths	5-year overall survival	P-value (long-rank)	Hazard ratio for death (95% CI)	P-value (Cox)
Tobacco use
No	12	8	50.0	0.924	Reference	0.924
Yes	73	51	41.1		1.037 (0.492–2.186)
Alcohol use
No	21	16	38.1	0.343	Reference	0.345
Yes	61	40	45.9		0.756 (0.423–1.351)
Clinical tumor status
T1–T2	27	16	63.0	0.031	Reference	0.034
T3–T4	61	46	32.8		1.858 (1.049–3.291)
Clinical nodal status
N0	41	24	53.7	0.020	Reference	0.022
N+	47	38	31.9		1.819 (1.089–3.038)
Clinical TNM stage*
Initial (I/II)	15	7	80.0	0.018	Reference	0.022
Advanced (III/IV)	73	55	34.2		2.513 (1.140–5.537)
Anatomic site
Oral cavity	69	48	44.9	0.905	Reference	0.905
Pharynx and larynx	19	14	31.6		1.037 (0.570–1.886)
Surgical margins
Negative	75	49	46.7	0.031	Reference	0.034
Positive	12	12	16.7		2.001 (1.054–3.799)
Extranodal extension
Negative (N0)	33	20	51.5	0.202	Reference
No (N+)	15	11	33.3		1.380 (0.660–2.882)	0.392
Yes (N+)	23	18	30.4		1.777 (0.938–3.367)	0.078
Perineural invasion
No	48	28	52.1	0.032	Reference	0.035
Yes	27	23	33.3		1.818 (1.043–3.169)
Vascular invasion
No	52	32	48.1	0.088	Reference	0.092
Yes	19	16	36.8		1.681 (0.919–3.073)
C228T mutation
No	82	42	16.7	0.003	Reference	0.023
Yes	6	6	52.9		2.708 (1.150–6.374)
C250T mutation
No	70	40	48.1	0.606	Reference	0.733
Yes	18	8	53.6		0.893 (0.465–1.715)
C228T or C250T mutation
No	64	45	46.9	0.445	Reference	0.446
Yes	24	17	29.2		1.243 (0.710–2.177)

^*Clinical stage according to TNM Classification of Malignant Tumors−7th ed. Bold values indicates the statistical significance (p ≤ 0.05).