Table 2.

Characteristics of the 570 Patients with Colon Cancer.^*

Characteristic	All Eligible Patients (N=570)	Patients with Tumors Exhibiting High-Frequency Microsatellite Instability (N=95)	Patients with Tumors Exhibiting Microsatellite Stability or Low-Frequency Microsatellite Instability (N=475)	P Value
Treatment — no. (%)				0.19
Adjuvant chemotherapy	283 (50)	53 (56)	230 (48)
No adjuvant chemotherapy	287 (50)	42 (44)	245 (52)
Age — yr	59.8±11.2	60.7±13.0	59.7±10.8	0.13
Sex — no. (%)				0.45
Male	326 (57)	51 (54)	275 (58)
Female	244 (43)	44 (46)	200 (42)
Stage of disease — no. (%)				0.18
II	312 (55)	58 (61)	254 (53)
III	258 (45)	37 (39)	221 (47)
Site of tumor — no. (%)†				<0.001
Proximal	257 (45)	84 (89)	173 (36)
Distal	305 (54)	9 (10)	296 (62)
Multiple	6 (1)	1 (1)	5 (1)
Tumor grade — no. (%)†				<0.001
Well differentiated (G1)	97 (17)	8 (9)	89 (19)
Moderately differentiated (G2)	376 (66)	49 (53)	327 (69)
Poorly differentiated (G3)	65 (11)	24 (26)	41 (9)
Undifferentiated (G4)	28 (5)	12 (13)	16 (3)
No. of positive nodes — no. (%)				0.21
0	312 (55)	58 (61)	254 (53)
1–4	128 (22)	15 (16)	113 (24)
>4	130 (23)	22 (23)	108 (23)
Vital status at 8 yr — no. (%)				0.03
Alive	385 (68)	73 (77)	312 (66)
Dead	185 (32)	22 (23)	163 (34)

^*Plus–minus values are means ± SD. P values for the comparison between patients with tumors exhibiting high-frequency microsatellite instability and patients with tumors exhibiting microsatellite stability or low-frequency microsatellite instability were calculated by the chi-square test for all variables except the mean age at diagnosis, for which an unpaired t-test was used. Because of rounding, not all percentages total 100.

^† Data pertaining to the site of the tumor and the tumor grade are not available for all 570 patients.