TABLE 5.

Univariable analysis of isolated regional failure and recurrence-free survival using a Cox proportional hazards model.

Variables	Isolated regional failure		RFS
	HR (95% CI)	p value	HR (95% CI)	p value
Age, y	1.01 (0.98–1.04)	.48	1.03 (1.01–1.05)	.0012
Sex		.43		.21
Female	Reference		Reference
Male	1.32 (0.66–2.65)		0.79 (0.54–1.14)
Tobacco use		.93		.21
Never smoker	Reference		Reference
Past or current user	0.97 (0.48–1.95)		0.79 (0.54–1.15)
Alcohol use		.89		.014
Never drinker	Reference		Reference
Past or current drinker	0.95 (0.46–1.94)		0.62 (0.43–0.91)
Primary site		.02		.0095
Maxillary alveolus	Reference		Reference
Hard palate	2.35 (1.15–4.81)		1.70 (1.14–2.53)
Elective neck dissection		.048		.028
Yes	Reference		Reference
No	4.24 (1.01–17.74)		1.88 (1.07–3.30)
Clinical T classification		.22		.26
Early T1–T2	Reference		Reference
Advanced T3–T4	0.61 (0.28–1.33)		1.23 (0.85–1.79)
Margins		.24		.077
Negative	Reference		Reference
Positive	1.58(0.73–3.42)		1.47 (0.96–2.27)
Pathologic T classification		.83		< .001
Early T1–T2	Reference		Reference
Advanced T3–T4	1.08 (0.52–2.25)		1.95 (1.34–2.82)
Perineural invasion		.34		.69
No	Reference		Reference
Yes	1.54 (0.63–3.74)		1.12 (0.65–1.93)
Lymphovascular invasion		.77		.25
No	Reference		Reference
Yes	0.81 (0.19–3.38)		1.47 (0.76–2.82)
Pathologic N classification		.15		.072
No neck dissection	Reference	.071	Reference	.024
N0	0.16 (0.02–1.17)	.44	0.45(0.23–0.90)	.58
N+	0.46 (0.06–3.34)		0.77 (0.31–1.90)
Adjuvant radiotherapy		.37		.89
No	Reference		Reference
Yes	0.62 (0.22–1.76)		1.04 (0.64–1.69)

Abbreviations: RFS, recurrence-free survival; HR, hazard ratio; 95% CI, 95% confidence interval.

The figures in bold indicate statistical significance.