Table 1.
Demographic and tumor characteristics of patients undergoing tLAR for RC.
| Characteristics | Derivation set | Training set | Test set | External validation set |
|---|---|---|---|---|
| Gender, n (%) | ||||
| Male | 1,030 (51.7) | 835 (52.3) | 195 (49.0) | 203 (49.0) |
| Female | 964 (48.3) | 761 (47.7) | 203 (51.0) | 211 (51.0) |
| Age at diagnosis, mean (SD), years | 60.20 (11.43) | 60.08 (11.59) | 60.67 (10.73) | 61.54 (10.67) |
| Age at diagnosis, n (%), years | ||||
| <60 | 885 (44.4) | 717 (44.9) | 168 (42.2) | 157 (37.9) |
| ≥60 | 1,109 (55.6) | 879 (55.1) | 230 (57.8) | 257 (62.1) |
| BMI, mean (SD), kg/m2 | 22.84 (2.96) | 22.836 (2.98) | 22.87 (2.91) | 22.49 (2.90) |
| BMI, n (%), kg/m2 | ||||
| <18.5 | 113 (5.7) | 95 (6.0) | 18 (4.5) | 25 (6.0) |
| ≥18.5, <25 | 1,437 (72.1) | 1,144 (71.7) | 293 (73.6) | 308 (74.4) |
| ≥25, <30 | 420 (21.1) | 337 (21.1) | 83 (20.9) | 74 (17.9) |
| ≥30 | 24 (1.2) | 20 (1.3) | 4 (1.0) | 7 (1.7) |
| Comorbidity, n (%) | ||||
| No | 1,377 (69.1) | 1,107 (69.4) | 270 (67.8) | 86 (20.8) |
| Yes | 617 (30.9) | 489 (30.6) | 128 (32.2) | 328 (79.2) |
| Neoadjuvant chemoradiotherapy, n (%) | ||||
| No | 1,893 (94.9) | 1,517 (95.1) | 376 (94.5) | 403 (97.3) |
| Yes | 101 (5.1) | 79 (4.9) | 22 (5.5) | 11 (2.7) |
| Tumor location, n (%), cm | ||||
| <5 | 422 (21.2) | 327 (20.5) | 95 (23.9) | 93 (28.6) |
| ≥5, <10 | 695 (34.9) | 570 (35.7) | 125 (31.4) | 144 (44.3) |
| ≥10 | 877 (44.0) | 699 (43.8) | 178 (44.7) | 88 (27.1) |
| Tumor size, mean (SD), cm | 3.53 (1.39) | 3.559 (1.42) | 3.43 (1.24) | 3.37 (1.14) |
| Tumor size, n (%), cm | ||||
| <5 | 1,681 (84.3) | 1,339 (83.9) | 342 (85.9) | 360 (87.0) |
| ≥5 | 313 (15.7) | 257 (16.1) | 56 (14.1) | 54 (13.0) |
| T stage, n (%) | ||||
| T0–T2 | 737 (37.0) | 573 (35.9) | 164 (41.2) | 348 (87.0) |
| T3–T4 | 1,257 (63.0) | 1,023 (64.1) | 234 (58.8) | 66 (15.9) |
| N stage, n (%) | ||||
| N0 | 1,313 (65.8) | 1,049 (65.7) | 264 (66.3) | 255 (61.6) |
| N1–2 | 681 (34.2) | 547 (34.3) | 134 (33.7) | 159 (38.4) |
| CEA, n (%) | ||||
| Normal | 1,327 (66.5) | 1,056 (66.2) | 271 (68.1) | 228 (55.1) |
| Elevated | 667 (33.5) | 540 (33.8) | 127 (31.9) | 186 (44.9) |
| CA19-9, n(%) | ||||
| Normal | 1,529 (76.7) | 1,212 (75.9) | 317 (79.6) | 257 (62.1) |
| Elevated | 465 (23.3) | 384 (24.1) | 81 (20.4) | 157 (37.9) |
| Duration of surgery, mean (SD), min | 188.59 (70.36) | 188.48 (70.59) | 189.06 (69.50) | 157.32 (56.06) |
| Estimated intraoperative blood loss, mean (SD), ml | 75.85 (47.37) | 76.06 (48.04) | 75.05 (44.61) | 70.08 (51.31) |
| Postoperative complication, n (%) | ||||
| No | 1,638 (82.1) | 1,314 (82.3) | 324 (81.4) | 378 (91.3) |
| Yes | 356 (17.9) | 282 (17.7) | 74 (18.6) | 36 (8.7) |
RC, rectal cancer; BMI, body mass index; SD, standard deviation; CEA, carcinoembryonic antigen; CA19-9, carbohydrate antigen 19-9; tLAR, total laparoscopic anterior resection.