Identifying optimal candidates for local treatment of the primary tumor among patients with de novo metastatic nasopharyngeal carcinoma: a retrospective cohort study based on Epstein–Barr virus DNA level and tumor response to palliative chemotherapy

Table 2 Multivariate analysis using step-wise method

Characteristic	HR	95% CI	P-value
EBV DNA level	2.13	1.58–2.88	< 0.001
Tumor response	1.34	1.02–1.77	0.036
N stage	1.40	1.02–1.91	0.036
Metastatic site
Lung vs. Bone	0.89	0.58–1.36	0.589
Liver vs. Bone	1.00	0.66–1.51	0.993
Distant nodal vs. Bone	0.98	0.52–1.84	0.956
Multiple vs. Bone	2.39	1.77–3.23	< 0.001
LRRT	0.76	0.59–0.98	0.037

All factors were involved in the analysis and five factors remained
Abbreviations: EBV Epstein-Barr virus, HR hazard ratio, CI confidence interval, LRRT locoregional radiotherapy
All potential prognostic factors were involved in the analysis and five factors remained
HRs were calculated for N stage (N2–3 vs. N0–1); LRRT (Yes vs. No); EBV DNA level (Detectable vs. Undetectable) and Tumor response (SD/PD vs. CR/PR)

ISSN: 1471-2407