Table 6.

Cox regression model of multivariable analysis for overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS) and local control rate of disease in the neck

	P value (OS)	P value (DFS)	P value (DSS)	P value (local control rate)
Group	.014	.021	.001	.024
Stage	.000	.000	.000	.003
Bilateral	.101	.146	.349	.378
Invasion	.003	.004	.046	.001
Residual	.000	.000	.000	.000
EBERs	.000	.000	.000	.000
Size	.978	.768	.982	.550

Group residue group and recurrence group, Invasion surgical specimens were invasion of the tissue or organ outside the lymph node, Bilateral patients have bilateral neck failed after first therapy