TABLE 1.
Subject and tumor characteristics of colon cancer resections in the Surveillance, Epidemiology, and End Results Program database from 1988 to 2002
| Characteristic | Overall no. (%)(N = 77,978) | Left-sided colon cancer (N = 33,434; 42.9%) | Right-sided colon cancer (N = 44,544; 57.1%) | P value |
|---|---|---|---|---|
| Survival (mo), median (95% CI) | 83 (81–84) | 89 (87–91) | 78 (77–80) | < .001 |
| Age at diagnosis (y), median (IQR) | 71 (62–79) | 69 (60–77) | 73 (64–80) | < .001 |
| Male sex, N (%) | 37,050 (47.5%) | 17,365 (51.9%) | 19,685 (44.2%) | < .001 |
| Race, N (%) | N = 77,800 | N = 33,344 | N = 44,456 | < .001 |
| White | 64,680 (83.1%) | 27,211 (81.6%) | 37,469 (84.3%) | |
| Black | 7,135 (9.2%) | 2,881 (8.6%) | 4,254 (9.6%) | |
| Other | 5,985 (7.7%) | 3,252 (9.8%) | 2,733 (6.2%) | |
| Marital status, N (%) | N = 75,242 | N = 32,177 | N = 43,065 | < .001 |
| Single | 31,722 (42.2%) | 12,470 (38.8%) | 19,252 (44.7%) | |
| Married | 43,520 (57.8%) | 19,707 (61.2%) | 23,813 (55.3%) | |
| Mean year of diagnosis | September 1995 | June 1995 | October 1995 | < .001 |
| Tumor size (mm) | N = 67.914 | N = 27,525 | N = 40,389 | < .001 |
| Median (IQR) | 45 (30–60) | 40 (30–53) | 46 (35–62) | |
| AJCC tumor stage | N = 77,481 | N = 33,205 | N = 44,276 | < .001 |
| I | 16,688 (21.5%) | 8,610 (25.9%) | 8,078 (18.2%) | |
| II | 29,175 (37.7%) | 11,382 (34.3%) | 17,793 (40.2%) | |
| III | 21,475 (27.7%) | 8,727 (26.3%) | 12,748 (28.8%) | |
| IV | 10,143 (13.1%) | 4,486 (13.5%) | 5,657 (12.8%) | |
| Tumor grade | N = 77,978 | N = 33,434 | N = 44,544 | < .001 |
| Grade I (well differentiated) | 8,309 (10.7%) | 4,095 (12.3%) | 4,214 (9.5%) | |
| Grade II (moderately differentiated) | 54,251 (69.6%) | 24,829 (74.5%) | 29,422 (66.1%) | |
| Grade III–IV (poorly differentiated or undifferentiated) | 15,418 (19.8%) | 4,510 (13.5%) | 10,908 (24.5%) | |
| No. of lymph nodes examined, median (IQR) | 10 (6–16) | 8 (4–13) | 11 (7–17) | < .001 |
| Nodal status, N (%) | N = 73,324 | N = 30,259 | N = 43,065 | < .001 |
| N0 | 44,532 (60.7%) | 18,543 (61.3%) | 25,989 (60.4%) | |
| N1 | 18,397 (25.1%) | 7,946 (26.3%) | 10,451 (24.3%) | |
| N2 | 10,395 (14.2%) | 3,770 (12.5%) | 6,625 (15.4%) |
95% CI, 95% confidence interval; IQR, interquartile range; AJCC, American Joint Committee on Cancer. Sample size is presented for each variable when data are not available for all subjects.