Table 1. Characteristics of all patients with locally advanced rectal cancer and outcomes for 833 patients in training group.
| Training Group | Validation Group | |||||||
| Variable | No. (%) | Local Control | Distant Control | Overall Survival | No. (%) | |||
| (n = 833) | 5 Year | P-value | 5 Year | P-value | 5 Year | P-value | (n = 84) | |
| Demographic Variables | ||||||||
| Gender | ||||||||
| Male | 490 (58.8) | 0.770 | 0.423 | 0.637 | 0.006 | 0.608 | 0.008 | 50 (59.5) |
| Female | 343 (41.2) | 0.787 | 0.725 | 0.682 | 34 (40.5) | |||
| Age, years | ||||||||
| < = 49 | 262 (31.4) | 0.738 | 0.354 | 0.649 | 0.191 | 0.609 | 0.097 | 29 (34.5) |
| 50–69 | 432 (51.9) | 0.802 | 0.699 | 0.668 | 50 (59.5) | |||
| > = 70 | 139 (16.7) | 0.772 | 0.637 | 0.604 | 5 (6.0) | |||
| Clinical Variables | ||||||||
| Tumor location | ||||||||
| Low (<5 cm) | 181 (21.7) | 0.656 | <0.001 | 0.638 | 0.221 | 0.563 | 0.011 | 26 (31.0) |
| Mid (5cm, 10 cm) | 570 (68.5) | 0.806 | 0.677 | 0.651 | 54 (64.3) | |||
| High (>10 cm) | 82 (9.8) | 0.846 | 0.719 | 0.715 | 4 (4.8) | |||
| CEA | ||||||||
| < = 5 | 406 (48.7) | 0.817 | 0.005 | 0.696 | 0.073 | 0.660 | 0.062 | 67 (79.8) |
| >5 | 427 (51.3) | 0.740 | 0.650 | 0.616 | 17 (20.2) | |||
| Pathological Variables | ||||||||
| Pathology | ||||||||
| Adenocarcinoma | 683 (82.0) | 0.773 | 0.947 | 0.683 | 0.184 | 0.653 | 0.128 | 79 (94.0) |
| MAC or SRC | 150 (18.0) | 0.792 | 0.625 | 0.574 | 5 (6.0) | |||
| Tumor grade | ||||||||
| Low-intermediate grade | 708 (85.0) | 0.788 | 0.119 | 0.681 | 0.272 | 0.643 | 0.356 | 65 (77.4) |
| High grade | 125 (15.0) | 0.713 | 0.630 | 0.612 | 19 (22.6) | |||
| pT classification | ||||||||
| T1 | 13 (1.6) | 0.587 | 0.003 | 0.539 | 0.002 | 0.539 | 0.001 | 0 (0) |
| T2 | 93 (11.2) | 0.83 | 0.711 | 0.676 | 3 (3.6) | |||
| T3 | 351 (42.1) | 0.836 | 0.756 | 0.725 | 81 (86.4) | |||
| T4 | 376 (45.1) | 0.714 | 0.589 | 0.550 | 0 (0) | |||
| pN classification | ||||||||
| N0 | 324 (38.9) | 0.837 | <0.001 | 0.774 | <0.001 | 0.775 | <0.001 | 14 (16.7) |
| N1a | 142 (17.1) | 0.753 | 0.699 | 0.683 | 13 (15.5) | |||
| N1b | 152 (18.2) | 0.793 | 0.638 | 0.539 | 24 (28.6) | |||
| N2a | 112 (13.4) | 0.734 | 0.581 | 0.548 | 18 (21.4) | |||
| N2b | 103 (12.4) | 0.619 | 0.451 | 0.396 | 15 (17.8) | |||
| Lymphovascular invasion | ||||||||
| Yes | 178 (21.4) | 0.780 | 0.956 | 0.610 | 0.139 | 0.547 | 0.019 | 42 (50.0) |
| No | 655 (78.6) | 0.776 | 0.691 | 0.666 | 42 (50.0) | |||
| Perineural invasion | ||||||||
| Yes | 111 (13.3) | 0.698 | 0.076 | 0.544 | 0.003 | 0.515 | 0.002 | 34 (41.5) |
| No | 722 (86.7) | 0.787 | 0.692 | 0.656 | 50 (58.5) | |||
| No. of metastatic lymph nodes | ||||||||
| = 0 | 324 (38.9) | 0.775 | <0.001 | 0.837 | 0.002 | 0.774 | <0.001 | 14 (16.7) |
| > = 1 | 509 (61.1) | 0.552 | 0.735 | 0.606 | 70 (83.3) | |||
| Treatment Variables | ||||||||
| Surgery type | ||||||||
| AR | 494 (59.3) | 0.832 | <0.001 | 0.689 | 0.087 | 0.660 | 0.012 | 51 (60.7) |
| APR | 339 (40.7) | 0.697 | 0.649 | 0.607 | 33 (39.3) | |||
| Adjuvant treatment | ||||||||
| No treatment | 252 (30.3) | 0.676 | <0.001 | 0.662 | 0.332 | 0.633 | 0.670 | 16 (19.0) |
| CT only | 277 (33.3) | 0.781 | 0.698 | 0.663 | 25 (29.8) | |||
| CRT only | 123 (14.8) | 0.822 | 0.718 | 0.612 | 3 (3.6) | |||
| CRT plus CT | 181 (21.7) | 0.905 | 0.697 | 0.628 | 40 (47.6) | |||
Note: Tumor location was determined the distance from anal verge by preoperative colonoscopy or digital examination.
Abreviations: pT stage, pathological T stage; pN stage, pathological N stage; CEA, carcinoembryonic antigen; MAC, mucinous adenocarcinoma; SRC, signet ring cell carcinoma; AR, anterior resection; APR, abdominoperineal resection; CT, chemotherapy; CRT, chemoradiotherapy.