Table 1.
Clinical characteristics of the study population (All patients, Training, Internal validation and External validation cohorts).
| Variables | All patients N = 1661 |
Training cohort N = 692 |
Internal validation cohort N = 297 |
External validation cohort N = 672 |
p-value | Adjusted p-value |
|---|---|---|---|---|---|---|
| Sex | 0.2 | 0.5 | ||||
| Male | 965 (58%) | 416 (60%) | 160 (54%) | 389 (58%) | ||
| Female | 696 (42%) | 276 (40%) | 137 (46%) | 283 (42%) | ||
| Age | 63 (55, 69) | 61 (54, 67) | 62 (54, 67) | 65 (57, 73) | <0.001 | <0.001 |
| ≤60 | 699 (42%) | 341 (49%) | 135 (45%) | 223 (33%) | <0.001 | <0.001 |
| >60 | 962 (58%) | 351 (51%) | 162 (55%) | 449 (67%) | ||
| Histopathological grade | 0.007 | 0.033 | ||||
| Well/Moderately differentiated | 1400 (84%) | 564 (82%) | 247 (83%) | 589 (88%) | ||
| Poorly differentiated | 261 (16%) | 128 (18%) | 50 (17%) | 83 (12%) | ||
| T status | 0.8 | 0.9 | ||||
| 1–3 | 1339 (81%) | 553 (80%) | 243 (82%) | 543 (81%) | ||
| 4 | 322 (19%) | 139 (20%) | 54 (18%) | 129 (19%) | ||
| N status | 0.2 | 0.5 | ||||
| 1 | 1099 (66%) | 441 (64%) | 201 (68%) | 457 (68%) | ||
| 2 | 562 (34%) | 251 (36%) | 96 (32%) | 215 (32%) | ||
| Risk stage | 0.2 | 0.5 | ||||
| Low | 915 (55%) | 363 (52%) | 174 (59%) | 378 (56%) | ||
| High | 746 (45%) | 329 (48%) | 123 (41%) | 294 (44%) | ||
| M status | ||||||
| 0 | 969 (58%) | 581 (84%) | 256 (86%) | 132 (20%) | ||
| 1 | 2 (0.1%) | 2 (0.3%) | 0 (0%) | 0 (0%) | ||
| x | 690 (42%) | 109 (15.7%) | 41 (14%) | 540 (80%) | ||
| MSI or MMR status | >0.9 | >0.9 | ||||
| MSS or pMMR | 1399 (91%) | 620 (91%) | 259 (90%) | 520 (91%) | ||
| MSI or dMMR | 144 (9%) | 63 (9%) | 28 (10%) | 53 (9.2%) | ||
| Unknown | 118 | 9 | 10 | 99 | ||
| Sidedness | 0.4 | 0.7 | ||||
| Left | 955 (58%) | 410 (59%) | 163 (55%) | 382 (57%) | ||
| Right | 706 (42%) | 282 (41%) | 134 (45%) | 290 (43%) | ||
| Lung metastasis | 83 (7.2%) | 53 (7.7%) | 20 (6.7%) | 10 (6.1%) | 0.7 | 0.9 |
| Unknown | 509 | 0 | 0 | 509 | ||
| Liver metastasis | 109 (9.5%) | 71 (10%) | 28 (9.4%) | 10 (6.1%) | 0.3 | 0.6 |
| Unknown | 509 | 0 | 0 | 509 | ||
| Bone metastasis | 8 (0.7%) | 6 (0.9%) | 1 (0.3%) | 1 (0.6%) | 0.9 | >0.9 |
| Unknown | 509 | 0 | 0 | 509 | ||
| Other metastasis | 59 (5%) | 35 (5.1%) | 13 (4.4%) | 11 (6.7%) | 0.5 | 0.7 |
| Unknown | 509 | 0 | 0 | 509 | ||
| KRAS | 0.5 | 0.7 | ||||
| Mutated | 505 (45%) | 321 (46%) | 134 (45%) | 50 (41%) | ||
| Wild-Type | 606 (55%) | 371 (54%) | 163 (55%) | 72 (59%) | ||
| Unknown | 550 | 0 | 0 | 550 | ||
| BRAF | 0.4 | 0.7 | ||||
| Mutated | 122 (11%) | 75 (11%) | 37 (13%) | 10 (8.3%) | ||
| Wild-Type | 959 (89%) | 598 (89%) | 250 (87%) | 111 (92%) | ||
| Unknown | 580 | 19 | 10 | 551 |
Comparisons were performed between training, internal validation and external validation cohorts.
p-values and adjusted p-values <0.05 are highlighted in bold.
MSI: Microsatellite Instability; MMR: Mismatch Repair; MSS: Microsatellite Stable; dMMR: deficient Mismatch Repair; pMMR: proficient Mismatch repair.