Table 1.
Baseline characteristics of the included data sets.
| Characteristics | Training and internal validation set (n=2703) | First external validation set (n=275) | Second external validation set (n=127) | |
| Sex, n (%) | ||||
|
|
Male | 1427 (52.8) | 165 (60.0) | 80 (62.9) |
|
|
Female | 1276 (47.2) | 110 (40.0) | 47 (37.0) |
| Age (years), mean (SD) | 65.9 (12.4) | 67.8 (12.0) | 64.1 (13.0) | |
| Longitudinal location, n (%) | ||||
|
|
Lower-third | 2069 (76.5) | 214 (77.8) | 53 (41.7) |
|
|
Mid-third | 336 (12.4) | 28 (10.2) | 61 (48.1) |
|
|
Upper-third | 298 (11.0) | 33 (12.0) | 13 (10.2) |
| Circular location, n (%) | ||||
|
|
Lesser curvature | 945 (34.9) | 95 (34.5) | 49 (38.6) |
|
|
Greater curvature | 557 (20.6) | 58 (21.1) | 27 (21.3) |
|
|
Posterior wall | 585 (21.6) | 68 (24.7) | 22 (17.3) |
|
|
Anterior wall | 607 (22.5) | 54 (19.6) | 29 (22.8) |
|
|
More than 2 areas involved | 9 (0.3) | 0 (0) | 0 (0) |
| Endoscopic size of the lesion (mm), mean (SD) | 21.7 (12.5) | 27.9 (16.2) | 21.7 (12.6) | |
| Morphology, n (%) | ||||
|
|
Elevated | 375 (13.9) | 101 (36.7) | 28 (22.1) |
|
|
Flat | 566 (20.9) | 98 (35.6) | 37 (29.1) |
|
|
Depressed | 1762 (65.2) | 76 (27.6) | 62 (48.8) |
| Ulcer, n (%) | ||||
|
|
Present | 504 (18.6) | 63 (22.9) | 16 (12.6) |
|
|
None | 2199 (81.4) | 212 (77.1) | 111 (87.4) |
| Curative resection, n (%) | ||||
|
|
Yes | 2010 (74.4) | 100 (36.4) | 87 (68.5) |
|
|
No | 693 (25.6) | 175 (63.6) | 40 (31.5) |