Table A1.

Characteristics of the Study Cohort

Characteristic	Stage II Patients: CALGB 9581
	All Patients		Patients With Tumors Analyzed for MMR-D		Patients With Tumors Analyzed for 18qLOH
	No.	%	No.	%	No.	%
No. of patients	1,738		939		353
Treatment
MoAb 17-1A	865	49.8	477	50.8	193	54.7
Observation	873	50.2	462	49.2	160	45.3
Age, years
Mean	64		65		64
Range	24–90		30–90		33–89
Sex
Female	837	48.2	447	47.6	160	45.3
Male	901	51.8	492	52.4	193	54.7
Tumor location
Distal	671	38.6	367	39.1	169	47.9
Proximal	1,048	60.3	569	60.6	183	51.8
Unknown	19	1.1	3	0.3	1	0.3
Tumor differentiation
Well	146	8.4	80	8.5	33	9.4
Moderate	1,305	75.1	709	75.5	278	78.8
Poor	262	15.1	140	14.9	40	11.3
Undifferentiated	6	0.4	4	0.4	0
Unknown	19	1.1	6	0.6	2	0.6
Mean nodes sampled	14.4		14.1		13.6
	Stage III Patients: CALGB 89803
	All Patients		Patients With Tumors Analyzed for MMR-D		Patients With Tumors Analyzed for 18qLOH
	No.	%	No.	%	No.	%
No. of patients	1,264		913		602
Treatment
FU/LV	629	49.8	458	50.2	302	50.2
IFL	635	50.3	455	49.8	300	49.8
Age, years
Mean	60		60		60
Range	21–85		21–85		24–85
Sex
Female	562	44.5	415	45.5	259	43.0
Male	702	55.5	498	54.5	343	57.0
Tumor location
Distal	521	41.2	382	41.8	286	47.5
Proximal	713	56.4	519	56.8	310	51.5
Unknown	30	2.4	12	1.3	6	1.0
Tumor differentiation
Well	70	5.5	50	5.5	32	5.3
Moderate	861	68.1	629	68.9	451	74.9
Poor	299	23.7	220	24.1	112	18.6
Undifferentiated	5	0.4	4	0.4	2	0.3
Unknown	29	2.3	10	1.1	5	0.8
Positive nodes
Mean	3.6		3.6		3.5
Range	1–29		1–29		1–24
Nodal ratio
Mean	0.30		0.30		0.31
Range	0–1		0–1		0–1
Nodes sampled
Mean	14.4		14.6		13.8
Range	1–99		1–99		1–99

Abbreviations: 18qLOH, loss of heterozygosity at chromosomal location 18q; CALGB, Cancer and Leukemia Group B; FU/LV, fluorouracil plus leucovorin; IFL, fluorouracil, leucovorin, and irinotecan; MMR-D, mismatch repair deficiency; MoAb 17-1A, monoclonal antibody 17-1A.