. Author manuscript; available in PMC: 2017 Jun 21.

Published in final edited form as: Int J Radiat Oncol Biol Phys. 2015 Apr 8;92(2):358–367. doi: 10.1016/j.ijrobp.2015.01.049

Table 3. Univariate Cox regression analysis of local failure and failure-free survival.

	Local failure			Failure-free survival

Characteristic	Hazard ratio	95% CI	P value	Hazard ratio	95% CI	P value
Age (y)	1.18	1.00-1.39	.05	1.13	0.97-1.32	.11
Sex	0.57	0.14-2.27	.42	0.50	0.15-1.68	.26
ICE	0.48	0.13-1.80	.28	0.57	0.18-1.77	.33
Nodes	3.35	0.83-13.6	.09	2.02	0.54-7.56	.30
Pre-CT volume, cm³	0.99	0.98-1.01	.48	0.99	0.98-1.01	.35
Pre-RT volume, cm³	1.03	1.00-1.05	.03	1.02	1.00-1.04	.06
CT to pre-RT MRI interval, wk	1.02	0.92-1.12	.75	1.02	0.94-1.10	.68
CT to RT interval, wk	1.02	0.92-1.12	.71	1.02	0.93-1.11	.67
AVR, cm³	0.97	0.94-0.99	.04	0.98	0.95-1.00	.09
RPVR, %	0.98	0.97-0.99	.003	0.98	0.97-0.99	.01
Response type (PR or CR vs PD or NR)	-	-	-	0.08	0.009-0.60	.02

Abbreviations: CI = confidence interval; CR = complete response; ICE = intracranial extension; AVR = absolute volume reduction; NR = no response; PD = progressive disease; PR = partial response; RPVR = relative percent volume reduction.

CT to pre-RT MRI represents the time from chemotherapy initiation to preradiation therapy MRI in weeks.

CT to RT interval represents the time from chemotherapy initiation to radiation start in weeks.

The hazard ratio for local failure based on response type could not be calculated because of the absence of any local failures in patients with CR or PR.