. Author manuscript; available in PMC: 2025 Sep 11.

Published in final edited form as: J Clin Oncol. 2006 Nov 20;24(33):5291–5297. doi: 10.1200/JCO.2006.06.8627

Table 2.

Multivariate Cox Regression Models for Event-Free Survival for Patients Who Achieved Initial Tumor Control

Parameter	Comparison^*	Favored Group	χ ²	Hazard Ratio	95% CI	P
Age	51 v 67 (difference of 16 years)	Younger	4.38	1.48	1.03 to 2.14	.036
T stage	2 v 4	T2	12.84	2.15	1.42 to 3.28	.0003
N stage	1 v 2	N1	7.53	1.61	1.14 to 2.25	.006
Chemotherapy	No v yes	Yes	8.68	2.53	1.36 to 4.69	.003
Tumor location	Other v OP	OP	9.27	2.40	1.37 to 4.22	.002
OPN	336 v 642 (difference of 306 ng/mL)	Lower	6.21	1.49	1.09 to 2.04	.012

Abbreviations: OP, oropharynx; OPN, osteopontin.

For variables with more than two categories, we present the hazard ratio corresponding to the distance between the upper and lower quartiles of the variable (age, OPN, T stage, N stage) to facilitate comparison; for dichotomies (chemotherapy and tumor location) the odds ratio compares the two categories.