Table 3. Multivariate Analysis for Survival in the 6900 Study Patients.

Factor	Hazard Ratio (95% CI)a
	All Patients	CRT Only	S+PORT Only
Type of treatment
CRT	1 [Reference]	ND	ND
S+PORT	0.66 (0.61-0.71)	ND	ND
Age, y
≤50	1 [Reference]	1 [Reference]	1 [Reference]
51-60	1.08 (0.97-1.20)	1.09 (0.96-1.25)	1.02 (0.86-1.22)
61-70	1.21 (1.09-1.35)	1.24 (1.08-1.42)	1.13 (0.95-1.36)
>70	1.84 (1.65-2.05)	1.75 (1.53-2.01)	1.93 (1.62-2.30)
Facility
Academic	1 [Reference]	1 [Reference]	1 [Reference]
Comprehensive community cancer program	1.10 (1.01-1.19)	1.15 (1.05-1.30)	1.01 (0.90-1.15)
Integrated network cancer program	0.99 (0.95-1.23)	1.04 (0.90-1.19)	1.14 (0.97-1.33)
Unknown	0.97 (0.77-1.21)	0.96 (0.72-1.26)	0.94 (0.63-1.35)
Year of diagnosis
2004-2006	1 [Reference]	1 [Reference]	1 [Reference]
2007-2009	0.95 (0.87-1.03)	0.91 (0.82-1.02)	1.01 (0.89-1.16)
2010-2012	0.86 (0.79-0.94)	0.83 (0.74-0.93)	0.92 (0.79-1.06)
Distance, miles
<10	1 [Reference]	1 [Reference]	1 [Reference]
10-19	0.94 (0.86-1.03)	0.98 (0.88-1.09)	0.92 (0.79-1.07)
20-29	0.96 (0.85-1.08)	0.96 (0.85-1.07)	0.97 (0.79-1.17)
≥30	0.98 (0.90-1.07)	0.97 (0.83-1.12)	1.01 (0.87-1.18)
Comorbidity index
1	1 [Reference]	1 [Reference]	1 [Reference]
2	1.15 (1.05-1.26)	1.09 (0.98-1.22)	1.26 (1.08-1.48)
3	1.55 (1.34-1.78)	1.61 (1.35-1.90)	1.46 (1.12-1.86)
Clinical T stage
cT1-cT2	1 [Reference]	1 [Reference]	1 [Reference]
cT3-cT4	1.37 (1.27-1.48)	1.27 (1.16-1.40)	1.62 (1.41-1.86)
Clinical N stage
cN0-cN1	1 [Reference]	1 [Reference]	1 [Reference]
cN2a-cN2c	1.51 (1.41-1.62)	1.64 (1.51-1.79)	1.30 (1.16-1.45)

Abbreviations: CRT, chemoradiotherapy; ND, not determined; S+PORT, surgery and postoperative radiotherapy.

^aMultivariate model included age, year of diagnosis, distance from facility, facility type, comorbidity index, clinical T stage, and clinical N stage.