TABLE 2.

Comparative Baseline Characteristics for Microsatellite Status

Characteristics	MSI(−), n = 4450	MSI(+), n = 636	OR	95% CI	P
Sex
Male	2713 (61.0)	387 (60.8)	1	Reference
Female	1737 (39.0)	249 (39.2)	1.05	0.85–1.19	0.96
Age, yrs
<60	2470 (55.5)	366 (57.5)	1	Reference
≥60	1980 (44.5)	270 (42.5)	0.92	0.78–1.09	0.33
Race
White	3811 (85.6)	558 (87.7)	1	Reference
Black	386 (8.3)	44 (6.9)	0.82	0.59–1.13	0.22
Other	271 (6.1)	34 (5.3)	0.86	0.59–1.24	0.41
Year
2010–2011	940 (21.1)	165 (25.9)	1	Reference
2012–2013	1506 (33.8)	196 (30.8)	0.74	0.59–0.93	0.01
2014–2015	2004 (45.0)	275 (43.2)	0.78	0.64–0.96	0.02
Comorbid (Charlson-Deyo)
0	3508 (78.8)	521 (81.9)	1	Reference
1	740 (16.6)	89 (14.0)	0.81	0.64–1.03	0.08
≥2	202 (4.5)	26 (4.1)	0.87	0.57–1.32	0.50
Clinical T stage
T1/T2	281 (6.4)	36 (5.7)	1	Reference
T3	3786 (85.6)	526 (83.2)	1.08	0.76–1.55	0.66
T4	358 (8.1)	70 (11.1)	1.53	0.99–2.35	0.06
Primary tumor size, cm
<2	632 (16.1)	92 (16.5)	1	Reference
2–5	2200 (56.1)	317 (57.0)	0.99	0.77–1.27	0.94
>5	1090 (27.8)	147 (26.4)	0.93	0.70–1.22	0.59
Differentiation
Well	352 (9.0)	51 (9.0)	1	Reference
Moderately	3116 (79.7)	417 (73.9)	0.92	0.68–1.26	0.62
Poorly	441 (11.3)	96 (17.0)	1.50	1.04–2.17	0.03
Radiotherapy dose, Gy
<50.4	667 (15.0)	102 (16.0)	1	Reference
≥50.4 and <54	3292 (74.0)	462 (72.6)	0.92	0.73–1.16	0.46
≥54	491 (11.0)	72 (11.3)	0.96	0.69–1.33	0.80
Time from XRT to surgery
≤2 mos	2347 (52.7%)	332 (52.2)	1	Reference
>2 mos	2103 (47.3)	304 (47.8)	1.02	0.87–1.21	0.80
Initial chemotherapy
Single agent	2495 (56.1)	355 (55.8)	1
Double agent	1833 (41.2)	255 (40.1)	0.98	0.82–1.16	0.80