Table 2.
Univariate analysis of predictors for TRG in the training and validation cohorts
| Variable | Training cohort | Validation cohort | ||||
|---|---|---|---|---|---|---|
| TRG 0–1 | TRG 2–3 | P | TRG 0–1 | TRG 2–3 | P | |
| No. of patients | 33 | 38 | 33 | 42 | ||
| Age (mean, y ± SD) | 52 ± 12 | 56 ± 12 | 0.199 | 55 ± 13 | 55 ± 11 | 0.827 |
| Gender | 0.671 | 0.627 | ||||
| Male | 21 (64%) | 26 (68%) | 16 (49%) | 18 (43%) | ||
| Female | 12 (36%) | 12 (32%) | 17 (51%) | 24 (57%) | ||
| Pretreatment T stage | 0.655 | 0.854 | ||||
| T2 | 0 | 0 | 2 (6%) | 4 (9%) | ||
| T3 | 25 (76%) | 27 (71%) | 28 (85%) | 34 (82%) | ||
| T4 | 8 (24%) | 11 (29% | 3 (9%) | 4 (9%) | ||
| Pretreatment N stage | 0.928 | 0.638 | ||||
| N0 | 5 (16%) | 7 (18%) | 10 (30%) | 11 (26%) | ||
| N1 | 14 (42%) | 16 (42%) | 16 (49%) | 18 (43%) | ||
| N2 | 14 (42%) | 15 (40%) | 7 (21%) | 13 (31%) | ||
| Tumor differentiation | 0.128 | 0.732 | ||||
| Well/Moderately | 19 (58%) | 15 (40%) | 24 (73%) | 32 (76%) | ||
| Poorly/Undifferentiated | 14 (42%) | 23 (60%) | 9 (27%) | 10 (24%) | ||
| Distance from the anal verge | 0.120 | 0.924 | ||||
| ≦5 cm | 13 (39%) | 22 (58%) | 13 (39%) | 17 (41%) | ||
| > 5 cm | 20 (61%) | 16 (42%) | 20 (61%) | 25 (59%) | ||
| Tumor length | 0.015 | 0.011 | ||||
| ≦4 cm | 19 (42%) | 11 (71%) | 19 (58%) | 12 (29%) | ||
| > 4 cm | 14 (58%) | 27 (29%) | 14 (42%) | 30 (64%) | ||
| Circumferential extent | 0.022 | 0.163 | ||||
| ≦50% | 12 (36%) | 5 (13%) | 9 (27%) | 18 (43%) | ||
| > 50% | 21 (64%) | 33 (87%) | 24 (73%) | 24 (57%) | ||
| Pre-treatment CEA level (mean, ng/ml; 95%CI) |
29 (16–43) | 25 (17–34) | 0.615 | 15 (11–18) | 14 (11–16) | 0.548 |
| Post- treatment CEA level (mean, ng/mL; 95%CI) | 4 (1–7) | 6 (4–9) | 0.233 | 5 (4–7) | 7 (4–9) | 0.343 |
| Normalization of post- treatment CEA Level | 0.037 | 0.187 | ||||
| Normal (< 5 ng/mL) | 26 (79%) | 21 (55%) | 23 (70%) | 23 (55%) | ||
| Elevated (≧5 ng/mL) | 7 (21%) | 17 (45%) | 10 (30%) | 19 (45%) | ||
| CEA clearance pattern | 0.028 | 0.016 | ||||
| Exponential decrease (R2≧0.9) | 19 (58%) | 12 (32%) | 21 (64%) | 15 (36%) | ||
| Non-exponential decrease (R2 < 0.9) | 14 (42%) | 26 (68%) | 12 (36%) | 27 (64%) | ||
| Concurrent chemotherapy | 0.135 | NA | ||||
| Capecitabine | 0 | 0 | 33 (44%) | 42 (56%) | ||
| Infusional fluorouracil | 15 (45%) | 24 (63%) | 0 | 0 | ||
| mFOLFOX6 | 48 (55%) | 14 (37%) | 0 | 0 | ||
Abbreviation: NA not applicable, TRG tumor regression grade
The p value in boldface means statistically significant, that is, less than 0.05