Table 3.

Inverse probability weighting-adjusted Cox regression of biological and radiological responses to induction chemotherapy in 821 patients with locally advanced nasopharynx of head and neck cancer

Covariates	Subgroup	DFS			OS			DMFS			LRFS
		HR	95%CI	P	HR	95%CI	P	HR	95%CI	P	HR	95%CI	P
Post-NAC cfEBV DNAa	cBR vs. Non-cBR	2.81	2.16–3.66	<0.01	2.34	1.68–3.26	<0.01	3.45	2.43–4.91	<0.01	1.89	1.27–2.82	<0.01
Post-NAC MRIa	CR vs. PR	2.34	1.05–5.25	0.04	2.21	0.74–6.62	0.16	1.79	0.68–4.70	0.24	2.70	0.86–8.43	0.09
	CR vs. SD/PD	4.98	2.15–11.55	<0.01	5.24	1.69–16.31	<0.01	3.30	1.20–9.13	0.02	5.57	1.74–17.85	<0.01
Response Phenotypesa	G1: cBR+CR (References)	1.00	–	–	1.00	–	–	1.00	–	–	1.00	–	–
	G3: cBR+PR	1.52	0.69–3.33	0.30	1.52	0.54–4.34	0.43	1.03	0.40–2.63	0.95	1.93	0.61–6.09	0.26
	G4: non-cBR+PR	4.44	2.01–9.84	<0.01	3.56	1.23–10.29	0.02	3.91	1.52–10.02	<0.01	4.02	1.25–12.95	0.02
	G5: cBR+SD/PD	2.81	1.14–6.95	0.03	2.51	0.77–8.24	0.13	0.80	0.21–3.12	0.75	5.03	1.40–18.01	0.01
	G6: non-cBR+SD/PD	6.60	2.85–15.29	<0.01	7.18	2.391.61	<0.01	5.09	1.90–13.63	<0.01	5.04	1.48–17.11	0.01

Abbreviations: cBR Complete biological response, cfEBV DNA Cell-free Epstein-Barr virus DNA, CI Confidence interval, CR Complete response, DFS Disease-free survival, DMFS Distant metastasis-free survival, HR Hazard ratio, LRFS Locoregional relapse-free survival, MRI Magnetic resonance imaging, NAC Neoadjuvant chemotherapy, non-cBR Non-complete biological response, OS Overall survival, PD Progression disease, PR Partial responses, SD Stable disease

^aThe following variables were adjusted via IPW algorithm: age (<45 vs. ≥45 years), sex (male vs. female), smoking (No vs. Yes), alcohol (No vs. Yes), pretreatment EBV DNA (<2 vs. ≥2 × 10³ copies/mL), T stage (T1-2 vs. T3-4), N stage (N0-1 vs. N2-3), IC regimens (TPF vs. GP vs. TP vs. PF vs. others), IC cycles (2 cycles vs. 3 cycles vs. 4 cycles), CCD (<160 vs. ≥160 mg/m²). Two-sided P-values were calculated using the chi-square test