Table 6.

Results of multivariate survival analysis using Cox proportional hazards model.

Parameters	P values	Hazard ratio (95% confidence interval)		Parameters	P values	Hazard ratio (95% confidence interval)
OS
Presence of ENE	0.011	3.220	(1.301–7.971)	Extent of ENE (no ENE as reference)
				Minor ENE (<4 mm)	0.069	2.720	(0.923–8.012)
				Major ENE (≥4 mm)	0.011	3.739	(1.351–10.345)
Age	0.010	1.053	(1.012–1.095)	Age	0.022	1.049	(1.007–1.093)
AJCC pT/tumor size	0.950	1.009	(0.763–1.335)	AJCC pT/tumor size	0.961	1.007	(0.756–1.342)
Perineural invasion	0.032	2.572	(1.087–6.086)	Perineural invasion	0.034	2.557	(1.074–6088)
AJCC pN stage	0.023	2.524	(1.138–5.595)	AJCC pN stage	0.027	2.467	(1.108–5.489)
DSS
Presence of ENE	0.009	6.260	(1.593–24.597)	Extent of ENE (no ENE as reference)
				Minor ENE (<4 mm)	0.153	3.352	(0.639–17.585)
				Major ENE (≥4 mm)	0.002	11.488	(2.543–51.889)
AJCC pT/tumor size	0.253	1.254	(0.851–1.850)	AJCC pT/tumor size	0.305	1.242	(0.821–1.880)
Perineural invasion	0.639	1.356	(0.380–4.840)	Perineural invasion	0.674	1.305	(0.377–4.518)
AJCC pN stage	0.158	2.356	(0.717–7.749)	AJCC pN stage	0.261	2.035	(0.590–7.019)
DFS
Presence of ENE	0.026	3.153	(1.145–8.684)	Extent of ENE (no ENE as reference)
				Minor ENE(<4 mm)	0.200	2.169	(0.664–7.086)
				Major ENE (≥4 mm)	0.004	5.700	(1.715–18.938)
AJCC pT/tumor size	0.164	1.254	(0.912–1.725)	AJCC pT/tumor size	0.277	1.205	(0.861–1.686)
Perineural invasion	0.813	1.143	(0.377–3.466)	Perineural invasion	0.707	1.231	(0.417–3.634)
AJCC pN stage	0.339	1.659	(0.588–4.684)	AJCC pN stage	0.456	1.496	(0.519–4.312)
Laterality of positive lymph nodes	0.011	8.358	(1.628–42.909)	Laterality of positive lymph nodes	0.013	7.834	(1.540–40.058)

Bold p values are significant P values.