Table 4.

Binary Logistic Regression, Factors Associated with Pathological Complete Response

Characteristic	Adjusted OR (95% CI)	p Value
nCRT to surgery interval, wk
6 – 8	Reference
< 6	0.79 (0.68–0.91)	0.0009
> 8	1.12 (1.02 – 1.28)	0.04
Rectal cancer resections annually, n
1 – 10	Reference
11 – 30	1.20 (0.95–1.51)	0.12
≥ 30	1.42 (1.12–1.80)	0.004
Treatment regimen
RT, 1 chemo agent	Reference
RT, ≥2 chemo agents	0.76 (0.68–0.85)	<0.0001
Radiation dose, Gy
<45	Reference
≥ 45	1.28 (0.99. 1.65)	<0.06
Histology
Adenocarcinoma	Reference
Mucinous	0.13 (0.08–0.22)	<0.001
Signet ring cell	0.78 (0.42–1.47)	0.45
Clinical stage
II	Reference
III	0.87 (0.78–0.96)	0.008
Tumor size, mm
0 – 25	Reference
25 – 40	1.14 (1.01, 1.28)	0.04
40 – 50	1.18 (1.02, 1.38)	0.03
>50	1.43 (1.24, 1.66)	<0.0001
Female sex	1.22 (1.10–1.36)	0.0002
Primary payer
Private	Reference
Not Insured	0.60 (0.44–0.80)	0.005
Medicaid	0.67 (0.52–0.85)	0.001
Medicare	1.03 (0.89–1.19)	0.74
Other government	1.22 (0.78–1.92)	0.38
Year of diagnosis
2006	Reference
2007	1.11 (0.88–1.39)	0.40
2008	1.05 (0.84–1.31)	0.66
2009	1.28 (1.04–1.59)	0.02
2010	1.31 (1.07–1.62)	0.01
2011	1.56 (1.28–1.92)	<0.001

Model also controlled for age, race, average income and education by zip code, hospital type and hospital location.

OR, odds ratio; nCRT, neoadjuvant chemoradiotherapy; RT, radiotherapy.