Table 1.
Demographics and clinicopathological characteristics of the training and internal validation cohort.
| Training cohort (n = 1556) | Internal validation cohort (n = 668) | P-value | |
|---|---|---|---|
| Age | 0.911 | ||
| 20–54 years | 338 (21.7%) | 142 (21.3%) | |
| 55–64 years | 606 (38.9%) | 261 (39.1%) | |
| 65–74 years | 505 (32.5%) | 212 (31.7%) | |
| 75+ years | 107 (6.9%) | 53 (7.9%) | |
| Race | 0.393 | ||
| Black | 71 (4.6%) | 29 (4.3%) | |
| White | 1,423 (91.5%) | 613 (91.8%) | |
| Other | 62 (4.0%) | 26 (3.9%) | |
| Sex | 0.336 | ||
| Female | 241 (15.5%) | 100 (15.0%) | |
| Male | 1,315 (84.5%) | 568 (85.0%) | |
| Tumor site | 0.398 | ||
| Cervical | 2 (0.1%) | 0 (0%) | |
| Upper third | 14 (0.9%) | 12 (1.8%) | |
| Middle third | 170 (10.9%) | 83 (12.4%) | |
| Lower third | 1,315 (84.5%) | 538 (80.5%) | |
| Abdominal esophagus | 15 (1.0%) | 8 (1.2%) | |
| Overlapping | 40 (2.6%) | 27 (4.0%) | |
| T stage | 0.794 | ||
| T1 | 175 (11.2%) | 78 (11.7%) | |
| T2 | 261 (16.8%) | 131 (19.6%) | |
| T3 | 1,034 (66.5%) | 410 (61.4%) | |
| T4 | 86 (5.5%) | 49 (7.3%) | |
| N stage | 0.307 | ||
| N0 | 1,025 (65.9%) | 439 (65.7%) | |
| N1 | 363 (23.3%) | 169 (25.3%) | |
| N2 | 97 (6.2%) | 40 (6.0%) | |
| N3 | 71 (4.6%) | 20 (3.0%) | |
| Histology Grade | 0.771 | ||
| Grade I | 81 (5.2%) | 39 (5.8%) | |
| Grade II | 685 (44.0%) | 291 (43.6%) | |
| Grade III | 776 (49.9%) | 329 (49.3%) | |
| Grade IV | 14 (0.9%) | 9 (1.3%) | |
| LODDS | 0.199 | ||
| >−1.6 | 280 (18.0%) | 133 (19.9%) | |
| ≤−1.6 | 536 (34.4%) | 216 (32.3%) | |
| ≤−2.8 | 740 (47.6%) | 319 (47.8%) | |
| Histology | 0.554 | ||
| Adenocarcinoma | 1,261 (81.0%) | 544 (81.4%) | |
| Squamous cell carcinoma | 295 (19.0%) | 124 (18.6%) | |
| Tumor size | 0.735 | ||
| 0–3 cm | 384 (24.7%) | 179 (26.8%) | |
| 3–5 cm | 430 (27.6%) | 168 (25.1%) | |
| 5–7 cm | 236 (15.2%) | 103 (15.4%) | |
| >7 cm | 169 (10.9%) | 75 (11.2%) | |
| Unknown | 337 (21.7%) | 143 (21.4%) |