Table 3. Multivariate analysis of factors associated with pCR in the training cohort (n=425).
| Variables | Logistic regression | Nomogram | ||||
|---|---|---|---|---|---|---|
| Training group (n=425) | ||||||
| Regression coefficient | SE | OR(95% CI) | P value | C-index | 95%CI | |
| Post-CRT DAV, cm | −0.175 | 0.076 | 0.840 (0.723-0.975) | 0.022 | ||
| Pre-CRT CEA level, ≤5 ng/ml | 0.695 | 0.326 | 2.004 (1.058-3.798) | 0.033 | ||
| Post-CRT CEA level, ≤5 ng/ml | 1.326 | 0.638 | 3.767 (1.080-13.148) | 0.038 | Training: 0.81 | 0.76-0.85 |
| Tumor pathology, mucinous or signet ring adenocarcinoma | 0.532 | 1.147 | 1.703 (0.628-7.884) | 0.642 | Validation: 0.75 | 0.59- 0.92 |
| Post-CRT tumor, cm size | −0.571 | 0.194 | 0.565 (0.386-0.827) | 0.003 | ||
| Post-CRT circumferential of tumor extent | −3.861 | 0.861 | 0.021 (0.004-0.114) | <0.001 | ||
Abbreviations: SE: Standard error; OR, odds ratio; CI, confidence interval; CRT: chemoradiotherapy; DAV: distance from the anal verge; CEA, carcinoembryonic antigen.