Table 1.

Multivariable Cox Proportional Hazards model of factors independently associated with overall survival in patients with clinical stage I-III esophageal cancer undergoing esophagectomy.

Variable	Hazard Ratio	95% Confidence Interval	p-value
Age (per year)	1.02	1.02–1.02	<0.001
Female Sex (reference: male)	0.87	0.81–0.93	<0.001
Race (reference: caucasian)
Black	1.05	0.93–1.18	0.46
Other	0.78	0.63–0.96	0.02
Year of diagnosis (per year)	0.99	0.98–1.00	0.06
CDCC Score (reference: 0)
1	1.12	1.06–1.19	<0.001
≥2	1.21	1.10–1.33	<0.001
Insurance (reference: none)
Private	0.95	0.80–1.13	0.58
Government	1.03	0.87–1.23	0.71
Treatment location (reference: metro)
Urban	1.13	1.06–1.20	<0.001
Rural	1.02	0.87–1.21	0.77
Facility location (reference: New England (CT,MA,ME,NH,RI,VT))
Middle Atlantic (NJ, NY, PA)	0.93	0.83–1.05	0.25
South Atlantic (DC, DE, FL, GA, MD, NC, SC, VA, WV)	1.09	0.98–1.22	0.12
East North Central (IL, IN, MI, OH, WI)	1.09	0.97–1.22	0.15
East South Central (AL, KY, MS, TN)	1.16	1.01–1.33	0.03
West North Central (IA, KS, MN, MO, ND, NE, SD)	0.95	0.84–1.08	0.46
West South Central (AR, LA, OK, TX)	0.97	0.84–1.13	0.73
Mountain (AZ, CO, ID, MT, NM, NV, UT, WY)	0.95	0.81–1.11	0.49
Pacific (AK, CA, HI, OR, WA)	0.85	0.74–0.97	0.02
Diagnosis and Treatment at Different Facilities (reference: same facility)	0.94	0.89–0.99	0.03
Distance Traveled to Facility (per mile)	1.00	1.00–1.00	0.94
Academic center (reference: nonacademic)	1.01	0.94–1.08	0.84
Clinical Stage (reference: stage I)
Stage II	1.65	1.49–1.83	<0.001
Stage III	1.96	1.75–2.20	<0.001
Squamous Cell Histology (reference: adenocarcinoma)	1.13	1.05–1.20	<0.001
Neoadjuvant Chemotherapy	1.07	0.96–1.20	0.20
Neoadjuvant Radiation	1.05	0.95–1.16	0.32
Center Esophagectomy Volume (increasing cases per year)
<9	0.97	0.95–0.98	<0.001
>9 and <30	0.99	0.98–1.00	0.001
>30	0.99	0.98–1.00	0.003
Interaction of Clinical Stage and Center Esophagectomy Volume			<0.001