Table 3.

Results of univariate analysis of selected prognostic factors for disease-free survival.

Characteristics	Number of cases	Numberv of recurrent cases	5-year disease-free survival	P-value (long-rank)	Hazard ratio for recurrence (95% CI)	P-value (Cox)
Tobacco use
No	12	6	42.4	0.237	Reference	0.243
Yes	73	23	63.7		0.585 (0.238–1.438)
Alcohol use
No	21	10	44.1	0.052	Reference	0.057
Yes	61	16	69.1		0.464 (0.210–1.025)
Clinical tumor status
T1–T2	27	10	59.8	0.811	Reference	0.811
T3–T4	61	20	60.5		1.097 (0.513–2.348)
Clinical nodal status
N0	41	10	70.8	0.040	Reference	0.045
N+	47	20	50.6		2.177 (1.017–4.660)
Clinical TNM stage*
Initial (I/II)	15	5	64.3	0.584	Reference	0.585
Advanced (III/IV)	73	25	59.6		1.307 (0.500–3.421)
Anatomic site
Oral cavity	69	23	61.7	0.937	Reference	0.937
Pharynx and larynx	19	7	52.6		0.967 (0.414–2.256)
Surgical margins
Negative	75	22	66.0	0.038	Reference	0.044
Positive	12	7	29.1		2.395 (1.022–5.612)
Extranodal extension
Negative (N0)	33	6	76.8	0.31	Reference
No (N+)	15	5	61.4		2.093 (0.639–6.862)	0.223
Yes (N+)	23	11	41.7		3.560 (1.312–9.660)	0.013
Perineural invasion
No	48	13	68.1	0.105	Reference	0.111
Yes	27	12	49.7		1.895 (0.864–4.158)
Vascular invasion
No	52	17	62.9	0.357	Reference	0.361
Yes	19	8	50.8		1.483 (0.637–3.451)
C228T mutation
No	82	26	63.0	0.017	Reference	0.025
Yes	6	4	20.0		3.372 (1.169–9.730)
C250T mutation
No	70	24	59.6	0.992	Reference	0.992
Yes	18	6	62.8		1.005 (0.410–2.461)
C228T or C250T mutation
No	64	20	63.3	0.250	Reference	0.254
Yes	24	10	51.2		1.557 (0.728–3.331)

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