Table 4.

Results of univariate and multivariate analyses

Parameter	TTP		p value	DSS		p value	OS		p value
	Univariate p value	Multivariate HR (95% CI)		Univariate p value	Multivariate HR (95% CI)		Univariate p value	Multivariate HR (95% CI)
Age (cont, favor younger age)	0.16	NI	NI	0.06	NI	NI	0.017	NI*	NI*
Sex (F vs. M)	0.31	NI	NI	0.25	NI	NI	0.76	NI	NI
Smoking status (cont, favor less PY)	0.35	NI	NI	0.2	NI	NI	0.0031	1.01 (1.00–1.02)	0.014
HPV/p16INK4A score
(1)HPV(NW)/p16INK4a(−)	—	—		—	—
(2)HPV(S)/p16INK4a(−) or HPV(NW)/p16INK4a(+)	0.2	0.55 (0.22—1.37)	.21	0.12	0.42 (0.16–1.12)	0.08	0.24	0.66 (0.29–1.51)	0.33
(3)HPV(S)/p16INK4a(+) Favor group 2 and 3	0.001	0.23 (0.08–0.69)	0.008	0.0007	0.11 (0.03–0.50)	0.004	0.0002	0.20 (0.07–0.61)	0.004
N-Classification (N0–1 vs. N2–3)	0.62	NI	NI	0.73	NI	NI	0.43	NI	NI
Hb (Cont, g/dL, favor higher level)	0.02	0.86 (0.69–1.06)	0.15	0.005	0.82 (0.66–1.02)	0.073	0.0015	0.79 (0.66–0.96)	0.017
Treatment (CRT vs. S+RT, favor CRT)	0.007	2.31 (1.09–4.88)	0.028	0.002	2.64 (1.20–5.84)	0.016	0.032	2.42 (1.11–5.28)	0.027

Abbreviations: CI = confidence interval; Cont = on a continuum; CRT = chemoradiation; DSS = disease-specific survival; F = female; Hb = hemoglobin; HPV = human papillomavirus; HR = hazard ratio; M = male; NI = not included; OS = overall survival; PY = pack year of cigarette use; RT = radiation; S = surgery; TTP = time to progression.

^*Age not included because it highly correlated with pack-year of cigarette use.