Table 3.

Mortality in patients with oral SCC between the non-operative and operative treatment groups during the 5-year follow-up period (n = 358)

	Univariate analysis					Multivariable analysis
	Crude HR	95% CI			P valuea	Adjusted HR	95% CI			P valuea
Sex, male vs. female	1.125	0.681	–	1.860	0.645	0.900	0.529	–	1.529	0.696
Age group, ≥85 years vs. <85 years	1.529	0.612	–	3.821	0.364	1.172	0.395	–	3.482	0.775
Primary site, tongue vs. otherb	1.015	0.622	–	1.658	0.951	1.478	0.888	–	2.460	0.133
T stage, T3 + T4a + T4b vs. Tis + T1 + T2	3.511	1.909	–	6.458	< 0.001	1.410	0.439	–	4.525	0.564
N stage, N1 + N2a + N2b + N3a + N3b vs. N0	4.161	2.531	–	6.842	< 0.001	2.660	1.417	–	4.991	0.002
Stage, stage3 + 4a + 4b + 4c vs stage0 + 1 + 2	4.201	2.139	–	8.252	< 0.001	1.541	0.388	–	6.118	0.539
Treatment, operation vs non-operation	0.183	0.108	–	0.310	< 0.001	0.276	0.156	–	0.489	< 0.001

SCC squamous cell carcinoma, HR hazard ratio, CI confidence interval

^a A Cox proportional hazard model was constructed using the variables with a P value < 0.1 in Table 2. M stage was not included because the percentage of M1 in those aged <85 years was zero

^b Other primary sites included the lower gingiva, upper gingiva, buccal mucosa, oral floor, lip, and palate