Table 1.
Initial characteristics.
| Variable | Total Cohort n = 124 |
Training Set n = 64 |
Testing Set n = 60 |
p-Value |
|---|---|---|---|---|
| Mean age at diagnosis (years) | 65 (SD: 10.75) | 62 (SD: 11.8) | 68 (SD: 8.4) | 0.65 |
| Gender (male/female) | 76/47 | 37/27 | 40/20 | 0.91 |
| Degree of differentiation | ||||
| Well differentiated (%) | 43 (35%) | 26 (40.6%) | 19 (31.7%) | 0.82 |
| Moderately differentiated (%) | 58 (47%) | 32 (50%) | 23 (38.3%) | 0.43 |
| Undifferentiated (%) | 15 (12%) | 1 (1.5%) | 14 (23.3%) | 0.59 |
| High-grade dysplasia (%) | 8 (6%) | 4 (6.3%) | 6 (10%) | 0.59 |
| Mean ACE rate (ng/mL) | 8 (SD: 12.27) | 6.8 (SD: 7.2) | 9.7 (SD: 16.8) | 0.80 |
| cT stage | ||||
| cT 1 (%) | 1 (0.8%) | 0 (0%) | 1 (1.6%) | 0.99 |
| cT 2 (%) | 16 (13%) | 7 (10.9%) | 9 (15%) | 0.96 |
| cT 3 (%) | 97 (78.2%) | 52 (81.3%) | 28 (46.7%) | 0.23 |
| cT 4 (%) | 10 (8%) | 5 (7.8%) | 4 (6.6%) | 0.82 |
| N+ (%) | 95 (76%) | 50 (78%) | 44 (73%) | 0.99 |
| pCR (%) | 14 (11%) | 9 (14%) | 5 (8%) | 0.75 |
| Radiotherapy | 124 (100%) | |||
| 3D-CRT | 70 (56.5%) | 53 (82.8%) | 17 (28.3%) | <0.0001 |
| IMRT | 54 (43.5%) | 11 (17.2%) | 43 (71.7%) | |
| 45 Gy to the pelvis only | 70 (56%) | 59 (92%) | 10 (16.7%) | 0.04 |
| 45 Gy to the pelvis + boost up to 50.4 Gy to the rectal tumor | 54 (44%) | 5 (8%) | 50 (83.3%) | 0.03 |
| Concomitant chemotherapy | 118 (95%) | 64 (100%) | 54 (90%) | 0.39 |
| Capecitabine | 97 (78%) | 56 (88%) | 41 (68%) | 0.37 |
| Folfox | 21 (17%) | 8 (12%) | 13 (21.7%) | 0.42 |
| Duration of neoadjuvant therapy (mean, days) | 39 (SD: 4.71) | 38 (SD: 4.67) | 39 (SD: 6.11) | 0.93 |
| Delay between the end of treatment and surgery (mean, days) | 58 (SD: 13.19) | 59 (SD: 12.08) | 56 (SD: 15.05) | 0.82 |