Table 1.
Participant Demographics and Colorectal Cancer Molecular Characteristics by Primary Tumor Location
| Characteristicsa | Total No. | Cecum | Ascending colon | Transverse colon | Descending colon | Sigmoid colon | Rectum | P valueb |
|---|---|---|---|---|---|---|---|---|
| All cases | 13,101 | 1,968 | 1,871 | 1,301 | 968 | 3,057 | 3,936 | |
| Sex | <0.001 | |||||||
| Female | 6,339 (48%) | 1,036 (53%) | 1,044 (56%) | 663 (51%) | 481 (50%) | 1,460 (48%) | 1,655 (42%) | |
| Male | 6,762 (52%) | 932 (47%) | 827 (44%) | 638 (49%) | 487 (50%) | 1,597 (52%) | 2,281 (58%) | |
| Mean age ± SD | 61.3 ± 13.3 | 63.2 ± 13.0 | 64.3 ± 13.4 | 62.7 ± 13.8 | 60.1 ± 13.6 | 61.1 ± 12.5 | 58.8 ± 13.2 | <0.001 |
| <50 (Early-onset) | 2,994 (23%) | 360 (18%) | 315 (17%) | 261 (20%) | 256 (26%) | 662 (22%) | 1,140 (29%) | |
| 50–69 | 6,071 (46%) | 879 (45%) | 793 (42%) | 561 (43%) | 437 (45%) | 1,512 (49%) | 1,889 (48%) | |
| ≥70 | 4,036 (31%) | 729 (37%) | 763 (41%) | 479 (37%) | 275 (28%) | 883 (29%) | 907 (23%) | |
| Year of diagnosis | <0.001 | |||||||
| Before 1995 | 1,963 (15%) | 345 (18%) | 288 (16%) | 231 (18%) | 173 (18%) | 571 (19%) | 355 (9%) | |
| 1995–2000 | 5,522 (43%) | 915 (48%) | 724 (39%) | 568 (44%) | 398 (42%) | 1,284 (43%) | 1,633 (43%) | |
| After 2000 | 5,345 (42%) | 666 (35%) | 824 (45%) | 486 (38%) | 376 (40%) | 1,145 (38%) | 1,848 (48%) | |
| Family history of colorectal cancer | <0.001 | |||||||
| Absent | 9,531 (75%) | 1,404 (74%) | 1,289 (72%) | 898 (71%) | 676 (72%) | 2,303 (78%) | 2,961 (78%) | |
| Present | 3,125 (25%) | 495 (26%) | 510 (28%) | 360 (29%) | 261 (28%) | 659 (22%) | 840 (22%) | |
| AJCC disease stage | <0.001 | |||||||
| I | 3,062 (25%) | 425 (23%) | 415 (23%) | 248 (20%) | 171 (19%) | 775 (28%) | 1,028 (29%) | |
| II and III | 7,677 (63%) | 1,206 (65%) | 1,187 (67%) | 836 (69%) | 630 (68%) | 1,686 (60%) | 2,132 (60%) | |
| IV | 1,378 (11%) | 232 (12%) | 166 (8.8%) | 130 (11%) | 122 (13%) | 333 (12%) | 395 (11%) | |
| MSI status | <0.001 | |||||||
| Non-MSI-high | 10,141 (83%) | 1,311 (71%) | 1,093 (62%) | 786 (67%) | 764 (84%) | 2,710 (94%) | 3,477 (95%) | |
| MSI-high | 2,081 (17%) | 528 (29%) | 669 (38%) | 393 (33%) | 148 (16%) | 170 (5.9%) | 173 (4.7%) | |
| CIMP status | <0.001 | |||||||
| Low/negative | 7,701 (84%) | 1057 (72%) | 838 (62%) | 664 (71%) | 589 (90%) | 2,024 (94%) | 2,529 (95%) | |
| High | 1,509 (16%) | 401 (28%) | 520 (38%) | 275 (29%) | 64 (10%) | 124 (5.8%) | 125 (4.7%) | |
| BRAF | <0.001 | |||||||
| Wild-type | 10,252 (89%) | 1,425 (82%) | 1,236 (74%) | 887 (79%) | 773 (92%) | 2,576 (95%) | 3,355 (96%) | |
| Mutant | 1,315 (11%) | 314 (18%) | 440 (26%) | 234 (21%) | 68 (8.1%) | 137 (5.1%) | 122 (3.5%) | |
| KRAS | <0.001 | |||||||
| Wild-type | 6,494 (67%) | 828 (55%) | 936 (67%) | 674 (71%) | 480 (67%) | 1,641 (70%) | 1,935 (68%) | |
| Mutant | 3,269 (33%) | 681 (45%) | 467 (33%) | 274 (29%) | 241 (33%) | 701 (30%) | 905 (32%) |
a
Percentage indicates the proportion of patients with a specific patient molecular characteristic among all patients or in strata of tumor location (cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum).
b
To compare categorical data between subgroups classified by the tumor location, the chi-square test was performed. To compare continuous variables, an analysis of variance was performed.
Abbreviations: AJCC, American Joint Committee on Cancer; CIMP, CpG island methylator phenotype; MSI, microsatellite instability; SD, standard deviation.