Table 2.
Clinical characteristics of patients in the training, internal, and external validation cohorts.
| Training cohort | Internal validation cohort | External validation cohort | p | |
|---|---|---|---|---|
| N | 196 | 80 | 48 | |
| Age (%) | 0.7325 | |||
| <65 | 125 (63.78) | 54 (67.50) | 33 (68.75) | |
| ≥65 | 71 (36.22) | 26 (32.50) | 15 (31.25) | |
| Gender (%) | 0.7467 | |||
| Male | 113 (57.65) | 50 (62.50) | 29 (60.42) | |
| Female | 83 (42.35) | 30 (37.50) | 19 (39.58) | |
| BMI (%) | 0.2748 | |||
| ≤18.5 | 39 (19.90) | 16 (20.00) | 16 (33.33) | |
| 18.5-25 | 137 (69.90) | 58 (72.50) | 27 (56.25) | |
| ≥25 | 20 (10.20) | 6 (7.50) | 5 (10.42) | |
| Anemia (%) | 0.2919 | |||
| YES | 60 (30.61) | 18 (22.50) | 11 (22.92) | |
| NO | 136 (69.39) | 62 (77.50) | 37 (77.08) | |
| PNI (%) | 0.2653 | |||
| <45 | 115 (58.97) | 41 (51.25) | 23 (47.92) | |
| ≥45 | 80 (41.03) | 39 (48.75) | 25 (52.08) | |
| Albumin (%) | 0.3874 | |||
| <40 | 141 (71.94) | 63 (78.75) | 33 (68.75) | |
| ≥40 | 55 (28.06) | 17 (21.25) | 15 (31.25) | |
| Neoadjuvant chemotherapy (%) | 0.0295 | |||
| YES | 22 (11.22) | 6 (7.50) | 11 (22.92) | |
| NO | 174 (88.78) | 74 (92.50) | 37 (77.08) | |
| ASA (%) | 0.7932 | |||
| I-II | 147 (75.00) | 63 (78.75) | 37 (77.08) | |
| III-IV | 49 (25.00) | 17 (21.25) | 11 (22.92) | |
| Surgical approach (%) | 0.529 | |||
| Laparotomy | 11 (5.61) | 3 (3.75) | 1 (2.08) | |
| Laparoscope | 185 (94.39) | 77 (96.25) | 47 (97.92) | |
| Operation time (%) | 0.5591 | |||
| <200 | 77 (39.29) | 29 (36.25) | 22 (45.83) | |
| ≥200 | 119 (60.71) | 51 (63.75) | 26 (54.17) | |
| Blood loss (%) | 0.9345 | |||
| <100 | 134 (68.37) | 53 (66.25) | 33 (68.75) | |
| ≥100 | 62 (31.63) | 27 (33.75) | 15 (31.25) | |
| Differentiation extent (%) | 0.8823 | |||
| Low | 47 (23.98) | 24 (30.00) | 13 (27.08) | |
| Medium | 134 (68.37) | 50 (62.50) | 31 (64.58) | |
| High | 15 (7.65) | 6 (7.50) | 4 (8.33) | |
| T staging (%) | 0.0928 | |||
| Tis | 5 (2.55) | 2 (2.50) | 2 (4.17) | |
| T1 | 9 (4.59) | 3 (3.75) | 0 (0.00) | |
| T2 | 34 (17.35) | 9 (11.25) | 9 (18.75) | |
| T3 | 80 (40.82) | 37 (46.25) | 30 (62.50) | |
| T4 | 68 (34.69) | 29 (36.25) | 7 (14.58) | |
| N staging (%) | 0.6449 | |||
| N0 | 110 (56.12) | 43 (53.75) | 27 (56.25) | |
| N1 | 55 (28.06) | 20 (25.00) | 10 (20.83) | |
| N2 | 31 (15.82) | 17 (21.25) | 11 (22.92) | |
| Pathologic stage (%) | 0.88 | |||
| I | 39 (19.90) | 12 (15.00) | 10 (20.83) | |
| II | 65 (33.16) | 30 (37.50) | 16 (33.33) | |
| III | 92 (46.94) | 38 (47.50) | 22 (45.83) | |
| Tumor diameter (%) | 0.052 | |||
| <5 | 103 (52.55) | 49 (61.25) | 34 (70.83) | |
| ≥5 | 93 (47.45) | 31 (38.75) | 14 (29.17) | |
| History of abdominal surgery (%) | 0.1925 | |||
| NO | 159 (81.12) | 70 (87.50) | 36 (75.00) | |
| YES | 37 (18.88) | 10 (12.50) | 12 (25.00) | |
| Tumor location (%) | 0.5807 | |||
| Rectum | 115 (58.67) | 51 (63.75) | 35 (72.92) | |
| Sigmoid | 19 (9.69) | 9 (11.25) | 3 (6.25) | |
| Descending colon | 13 (6.63) | 7 (8.75) | 1 (2.08) | |
| Transverse colon | 6 (3.06) | 1 (1.25) | 1 (2.08) | |
| Ascending colon | 43 (21.94) | 12 (15.00) | 8 (16.67) | |
| Hypertension (%) | 0.7577 | |||
| NO | 150 (76.53) | 63 (78.75) | 39 (81.25) | |
| YES | 46 (23.47) | 17 (21.25) | 9 (18.75) | |
| Diabetes (%) | 0.229 | |||
| NO | 177 (90.31) | 77 (96.25) | 43 (89.58) | |
| YES | 19 (9.69) | 3 (3.75) | 5 (10.42) | |
| Cardiovascular (%) | 0.8681 | |||
| NO | 186 (94.90) | 75 (93.75) | 46 (95.83) | |
| YES | 10 (5.10) | 5 (6.25) | 2 (4.17) | |
| COPD (%) | 0.7491 | |||
| NO | 184 (93.88) | 76 (95.00) | 44 (91.67) | |
| YES | 12 (6.12) | 4 (5.00) | 4 (8.33) | |
| Cerebral infarction (%) | 0.0694 | |||
| NO | 192 (97.96) | 75 (93.75) | 48 (100.00) | |
| YES | 4 (2.04) | 5 (6.25) | 0 (0.00) | |
| NLR (mean (SD)) | 3.694 (3.037) | 3.198 (1.933) | 3.190 (2.209) | 0.2651 |