Table 2.
Characteristics of patients and lesions in the training and validation group.
| Variables | All subjects (N = 1096) | Training group (N = 877) | Validation group (N = 219) | p value |
|---|---|---|---|---|
| Sex (n [%]) | 0.068 | |||
| Male | 618 (56.4) | 507 (57.8) | 111 (50.7) | |
| Female | 478 (43.6) | 370 (42.2) | 108 (49.3) | |
| Age (years), median (IQR) | 54.0 (46.0–64.0) | 54.0 (46.0–64.0) | 55.0 (46.0–63.0) | 0.860 |
| Medication history (n [%]) | ||||
| Use of Antithrombotics | 30 (2.7) | 26 (3.0) | 4 (1.8) | 0.489 |
| Use of Immunosuppressants | 3 (0.3) | 1 (0.1) | 2 (0.9) | 0.104 |
| Use of NSAIDs | 4 (0.4) | 3 (0.3) | 1 (0.5) | 1.000 |
| Comorbidity (n [%]) | ||||
| Hypertension | 191 (17.4) | 155 (17.7) | 36 (16.4) | 0.740 |
| Diabetes mellitus | 40 (3.6) | 33 (3.8) | 7 (3.2) | 0.843 |
| History of malignancy | 51 (4.7) | 46 (5.2) | 5 (2.3) | 0.093 |
| History of abdominal operation | 119 (10.9) | 97 (11.1) | 22 (10.0) | 0.756 |
| History of intestinal polyp removal | 31 (2.8) | 27 (3.1) | 4 (1.8) | 0.440 |
| Tumor size (mm), median (IQR) | 15.0 (10.0–23.0) | 15.0 (10.0–23.0) | 15.0 (10.0–23.0) | 0.768 |
| Tumor location (n [%]) | 0.099 | |||
| Right-side colon a | 148 (13.5) | 119 (13.6) | 29 (13.2) | |
| Left-side colon b | 178 (16.2) | 132 (15.1) | 46 (21.0) | |
| Rectum | 770 (70.3) | 626 (71.4) | 144 (65.8) | |
| Pathological invasion depth (n [%]) | 0.221 | |||
| Mucosal layer | 593 (54.1) | 463 (52.8) | 130 (59.4) | |
| Submucosal layer | 479 (43.7) | 394 (44.9) | 85 (38.8) | |
| Others | 24 (2.2) | 20 (2.3) | 4 (1.8) | |
| Histological findings (n [%]) | 0.475 | |||
| Adenoma (LGIN + HGIN) | 441 (40.2) | 347 (39.6) | 94 (42.9) | |
| Adenocarcinoma | 149 (13.6) | 119 (13.6) | 30 (13.7) | |
| Submucosal benign lesion | 412 (37.6) | 339 (38.7) | 73 (33.3) | |
| Others | 94 (8.6) | 72 (8.2) | 22 (10.0) | |
| Morphology (n [%]) | 0.304 | |||
| 0-Is/Ip | 99 (9.0) | 76 (8.7) | 23 (10.5) | |
| LST | 508 (46.4) | 400 (45.6) | 108 (49.3) | |
| SMT | 489 (44.6) | 401 (45.7) | 88 (40.2) | |
| Resection (n [%]) | 0.093 | |||
| Complete en bloc resection | 960 (87.6) | 776 (88.5) | 184 (84.0) | |
| Piecemeal resection | 136 (12.4) | 101 (11.5) | 35 (16.0) | |
| Injury to muscle layer (n [%]) | 478 (43.6) | 385 (43.9) | 93 (42.5) | 0.759 |
| Non-lifting sign (n [%]) | 192 (17.5) | 151 (17.2) | 41 (18.7) | 0.671 |
| Electrocoagulation for ESD ulcer (n [%]) | 825 (75.3) | 658 (75.0) | 167 (76.3) | 0.773 |
| Complete ESD ulcer closure (n [%]) | 914 (83.4) | 729 (83.1) | 185 (84.5) | 0.705 |
| Inadequate bowel preparation (n [%]) | 67 (6.1) | 53 (6.0) | 14 (6.4) | 0.972 |
| Intraoperative perforation (n [%]) | 77 (7.0) | 59 (6.7) | 18 (8.2) | 0.532 |
| Intraoperative bleeding (n [%]) | 206 (18.8) | 164 (18.7) | 42 (19.2) | 0.948 |
| ESD procedure time (min), median (IQR) | 26.0 (17.0–40.0) | 25.0 (16.0–40.0) | 28.0 (18.0–45.0) | 0.177 |
| Operator (n [%]) | 0.768 | |||
| Trainee | 210 (19.2) | 166 (18.9) | 44 (20.1) | |
| Expert | 886 (80.8) | 711 (81.1) | 175 (79.9) | |
| Immediate antibiotics therapy (n [%]) | 195 (17.8) | 149 (17.0) | 46 (21.0) | 0.197 |
| Hospitalization, median (IQR) | 7.0 (5.0–9.0) | 7.0 (5.0–8.0) | 7.0 (6.0–9.0) | 0.142 |
| Fasting period, median (IQR) | 2.0 (2.0–3.0) | 2.0 (2.0–3.0) | 2.0 (2.0–3.0) | 0.910 |
| Fever | 204 (18.6) | 161 (18.4) | 43 (19.6) | 0.736 |
IQR, interquartile range; NSAIDs, Non-Steroidal Anti-Inflammatory Drugs; LGIN, low-grade intraepithelial neoplasia; HGIN, high-grade intraepithelial neoplasia; Is, sessile configuration; Ip, pedunculated configuration; LST, laterally spreading tumor; SMT, submucosal tumor; ESD, endoscopic submucosal dissection.
aRight-side colon: cecum, ascending colon, and transverse colon.
bLeft-side colon: descending colon and sigmoid colon.