Table 4. Summary of multivariate analysis of prognostic factors in 481 nasopharyngeal carcinoma patients with retropharyngeal lymph node metastasis (RLN) metastasis.

Endpoint	Variable	B	P *	HR	95% CI for HR
Disease failure	Age (≤50 vs. 50)	0.659	<0.001	1.933	1.374–2.721
	T-classification	0.330	<0.001	1.391	1.167–1.658
	N-classification	0.349	<0.001	1.417	1.203–1.670
	Necrosis	0.585	0.003	1.795	1.214–2.654
	MID (<10 vs. ≥10 mm)	0.329	0.063	1.389	0.983–1.964
Distant failure	Age (≤50 vs. 50 years)	0.412	0.064	1.510	0.976–2.335
	T-classification	0.318	0.004	1.374	1.107–1.706
	N-classification	0.413	<0.001	1.511	1.249–1.828
	Necrosis	0.561	0.018	1.752	1.100–2.790
	MID (<10 vs. ≥10 mm)	0.490	0.026	1.632	1.059–2.515
Locoregional recurrence	Necrosis	0.961	0.005	2.614	1.339–5.103
	MID (<10 vs. ≥10 mm)	0.570	0.083	1.767	0.929–3.364

Abbreviations: CI  =  confidence interval, MID = minimal axial diameters.

*P values were calculated using an adjusted Cox proportional-hazards model. The following known important prognostic variables were included in the Cox proportional hazards model: minimal axial diameters of RLN (<10 vs. ≥10 mm MID), necrosis of RLN (no vs. yes), laterality of RLN (unilateral vs. bilateral) and extra nodal neoplastic spread of RLN (no vs. yes), age (≤50 vs. 50), sex, T-classification, N-classification and chemotherapy (no vs. yes).