Table 2.

The results of the multivariate analysis of malignant transformation factors by the Cox proportional hazards regression model

Characteristics	Assigned score	Event‐free survival	P‐value
		Hazard ratio (95% CI)
Age (years)
≤65	0	1.902 (0.794–4.902)	0.151
>65	1
Sex
Male	0	1.098 (0.469–2.705)	0.831
Female	1
Oral subsite
Tongue	0	1.305 (0.546–3.151)	0.547
Others	1
Grade of dysplasia
None	0	1.191 (0.492–2.792)	0.689
Mild, moderate, severe	1
SMAD4 expression
High	0	2.632 (1.031–7.654)	0.043a
Low	1
Lymphocyte infiltration
Low	0	2.670 (0.729–17.24)	0.152
High	1

CI, confidence interval.

^a P < 0.05.