Table 1 Summarized distribution of essential characteristics of the discovery and validation cohorts
| Â | Discovery cohort (WCH) | Validation cohort (PUCHI) | p-value* |
|---|---|---|---|
Variables | n = 728 | n = 413 |  |
Basic characteristicsa | |||
 Gender | |||
  Male | 406 (55.8%) | 239 (57.9%) | 0.532 |
  Female | 322 (44.2%) | 174 (42.1%) |  |
  Age (years) | 62.0 (54.0–70.0) | 62.0 (55.0–70.0) | 0.538 |
 Surgical procedure | |||
  Open | 519 (71.3%) | 296 (71.7%) | 0.946 |
  Laparoscopic | 209 (28.7%) | 117 (28.3%) |  |
 Tumor site | |||
  Right colon | 49 (6.7%) | 36 (8.7%) |  < 0.001 |
  Left colon | 109 (15.0%) | 104 (25.2%) |  |
  Rectum | 570 (78.3%) | 273 (66.1%) |  |
Tumor size (cm) | 3.0 (2.0–3.5) | 2.8 (2.0–4.0) | 0.854 |
Follow-up (months) | 62.0 (53.0–71.0) | 63.0 (41.0–77.0) | 0.065 |
Candidate risk factors | |||
CEA (ng/ml) | 2.4 (1.5–3.7) | 2.3 (1.4–3.7) | 0.411 |
 Grade | |||
  G1 + G2 | 578 (80.3%) | 383 (92.7%) |  < 0.001 |
  G3 + G4 | 142 (19.7%) | 30 (7.3%) |  |
 T stage | |||
  T1 | 170 (23.4%) | 100 (24.2%) | 0.798 |
  T2 | 558 (76.6%) | 313 (75.8%) |  |
No. lymph nodes retrieval | 12.0 (8.0–16.0) | 12.0 (8.0–15.0) | 0.995 |
Lymphovascular invasion | 30 (4.1%) | 19 (4.6%) | 0.817 |
Perineural invasion | 18 (2.5%) | 15 (3.6%) | 0.348 |