Table 2.

Univariate and multivariable analysis of DM in the training cohort for clinical model construction

Covariate	Univariate analysis			Multivariate analysis
	HR	95% CI	p value	HR	95% CI	p value
Age, years	1.00	0.97–1.03	0.88	0.99	0.96–1.03	0.68
Sex assigned at birth
Male	Reference			Reference
Female	0.29	0.11–0.74	0.009	0.35	0.13–0.90	0.03
Ta category
T1	Reference			Reference
T2	2.27	1.19–4.30	0.01	2.54	1.27–5.08	0.008
Na category
N0	Reference			Reference
N1	2.61	0.63–10.80	0.19	1.82	0.38–8.65	0.45
LDHb
Normal	Reference			Reference
Abnormal	2.25	0.70–7.29	0.18	2.20	0.67–7.24	0.19
EBV DNAc
Undetectable	Reference			Reference
Detectable	3.24	1.65–6.37	0.001	1.74	0.83–3.64	0.14
rENE
Without	Reference			Reference
G1	3.82	1.95–7.49	<0.001	2.98	1.43–6.20	0.004
G2	15.53	6.67–36.14	<0.001	9.51	3.62–24.96	<0.001
Chemotherapy
No	Reference			Reference
Yes	1.90	0.88–4.10	0.10	1.01	0.44–2.35	0.97

G1: Coalescent nodes; G2: Adjacent structures infiltration.

Abbreviations: DMFS, distant metastasis-free survival; OS, overall survival; HR, hazard ratio; CI, confidence interval; LDH, Lactate dehydrogenase; EBV DNA, Epstein-Barr virus deoxyribonucleic acid; rENE, radiologic extranodal extension.

^aAccording to the eighth edition of the American Joint Committee on Cancer/Union for International Cancer Control cancer staging manual.

^bAbnormal, center 1: >245 U/L, center 2 and center 3: >250U/L.

^cDetectable thresholds, center 1: <1000copy/mL, center 2: <500copy/mL, center 3: <500copy/mL.