Table 4.
Univariate analysis of predictors for pCR in the training and validation cohorts
| Variable | Training cohort | Validation cohort | ||||
|---|---|---|---|---|---|---|
| pCR | No pCR | P | pCR | No pCR | P | |
| No. of patients | 11 | 60 | 10 | 65 | ||
| Age (mean, y ± SD) | 57 ± 12 | 54 ± 13 | 0.323 | 55 ± 13 | 55 ± 12 | 0.910 |
| Gender | 0.618 | 0.497 | ||||
| Male | 8 (73%) | 39 (65%) | 6 (60%) | 28 (43%) | ||
| Female | 3 (27%) | 21 (35%) | 4 (40%) | 37 (57%) | ||
| Pretreatment T stage | 0.267 | 0.546 | ||||
| T2 | 0 | 0 | 1 (10%) | 5 (8%) | ||
| T3 | 10 (9%) | 42 (70%) | 9 (90%) | 53 (81%) | ||
| T4 | 1 (91%) | 18 (30%) | 0 | 7 (11%) | ||
| Pretreatment N stage | 0.217 | 0.121 | ||||
| N0 | 2 (18%) | 10 (17%) | 4 (40%) | 17 (26%) | ||
| N1 | 7 (64%) | 23 (38%) | 6 (60%) | 28 (43%) | ||
| N2 | 2 (18%) | 27 (45%) | 0 | 20 (31%) | ||
| Tumor differentiation | 0.073 | 0.707 | ||||
| Well/Moderately | 8 (73%) | 26 (43%) | 7 (70%) | 49 (75%) | ||
| Poorly/Undifferentiated | 3 (27%) | 34 (57%) | 3 (30%) | 16 (25%) | ||
| Distance from the anal verge | 0.301 | 0.731 | ||||
| ≦5 cm | 7 (64%) | 28 (53%) | 3 (30%) | 27 (42%) | ||
| > 5 cm | 4 (36%) | 32 (47%) | 7 (70%) | 38 (58%) | ||
| Tumor length | 0.044 | 0.509 | ||||
| ≦4 cm | 8 (73%) | 22 (37%) | 3 (30%) | 28 (43%) | ||
| > 4 cm | 3 (27%) | 38 (63%) | 7 (70%) | 37 (57%) | ||
| Circumferential extent | 0.441 | 0.480 | ||||
| ≦50% | 4 (36%) | 13 (22%) | 5 (50%) | 22 (34%) | ||
| > 50% | 7 (64%) | 47 (78%) | 5 (50%) | 43 (66%) | ||
| Pre-treatment CEA level (mean, ng/mL; 95%CI) | 24 (10–38) | 28 (19–37) | 0.709 | 13 (11–15) | 20 (10–30) | 0.165 |
| Post- treatment CEA level (mean, ng/mL; 95%CI) | 2 (0.2–4) | 6 (4–8) | 0.164 | 6 (2–11) | 6 (5–7) | 0.808 |
| Normalization of post- treatment CEA Level | 0.312 | 1.000 | ||||
| Normal (< 5 ng/mL) | 9 (82%) | 38 (63%) | 6 (60%) | 40 (62%) | ||
| Elevated (≧5 ng/mL) | 2 (18%) | 22 (37%) | 4 (40%) | 25 (38%) | ||
| CEA clearance pattern | 0.008 | 0.042 | ||||
| Exponential decrease (R2≧0.9) | 9 (82%) | 22 (37%) | 8 (80%) | 28 (43%) | ||
| Non-exponential decrease (R2 < 0.9) | 2 (18%) | 38 (63%) | 2 (20%) | 37 (57%) | ||
| Concurrent chemotherapy | 0.743 | NA | ||||
| Capecitabine | 0 | 0 | 10 (13%) | 65 (87%) | ||
| Infusional fluorouracil | 7 (64%) | 32 (47%) | 0 | 0 | ||
| mFOLFOX6 | 4 (36%) | 28 (53%) | 0 | 0 | ||
Abbreviation: NA not applicable, pCR pathologic complete response
The p value in boldface means statistically significant, that is, less than 0.05