Table 3.
Cox regression on factors associated with overall survival and disease-free survival
| Variable | Univariable analysis |
Multivariable analysis |
||
|---|---|---|---|---|
| Hazard ratio (95% CI) | P-value | Hazard ratio (95% CI) | P-value | |
| Overall survival | ||||
| Age | 1.04 (1.02–1.05) | <0.001 | 4.18 (1.94–9.01) | <0.001 |
| Sex | ||||
| Male | 1.00 (reference) | - | 1.00 (reference) | - |
| Female | 0.45 (0.28–0.70) | 0.001 | 0.50 (0.32–0.80) | 0.003 |
| ASA PS classification | ||||
| I | 1.00 (reference) | - | 1.00 (reference) | - |
| II | 1.72 (1.15–2.57) | 0.008 | 1.39 (0.92–2.09) | 0.120 |
| III | 6.81 (3.28–14.15) | <0.001 | 3.77 (1.70–8.36) | 0.001 |
| Body mass index | 0.99 (0.93–1.06) | 0.810 | - | - |
| Pretreatment CEA | 1.00 (1.00–1.00) | 0.630 | - | - |
| Tumor location from the anal verge (cm) | ||||
| ≥12 | 1.00 (reference) | - | - | |
| 8–12 | 1.53 (0.21–11.27) | 0.680 | - | |
| 4–8 | 2.05 (0.28–14.76) | 0.480 | - | |
| <4 | 1.88 (0.25–13.85) | 0.540 | - | |
| Operative name | ||||
| Low anterior resection | 1.00 (reference) | - | 1.00 (reference) | - |
| Ultralow anterior resection | 1.56 (1.07–2.28) | 0.020 | 1.58 (1.08–2.32) | 0.020 |
| Abdominoperineal resection | 1.35 (0.66–2.75) | 0.410 | 1.12 (0.54–2.30) | 0.770 |
| Circumferential resection margin | ||||
| Negative | 1.00 (reference) | - | - | |
| Positive | 2.36 (0.87–6.40) | 0.090 | - | - |
| Tumor response to preoperative CRT | ||||
| pCR (ypT0N0) | 1.00 (reference) | <0.001 | 1.00 (reference) | - |
| Residual disease | 3.95 (1.84–8.48) | - | 4.18 (1.94–9.01) | <0.001 |
| Postoperative chemotherapy | ||||
| No | 1.00 (reference) | - | - | - |
| Yes | 0.82 (0.52–1.29) | 0.390 | - | - |
| Disease-free survival | ||||
| Age | 1.02 (1.01–1.04) | 0.003 | 1.02 (1.01–1.04) | 0.007 |
| Sex | ||||
| Male | 1.00 (reference) | - | 1.00 (reference) | - |
| Female | 0.56 (0.39–0.81) | 0.002 | 0.65 (0.45–0.94) | 0.020 |
| ASA PS classification | ||||
| I | 1.00 (reference) | - | 1.00 (reference) | - |
| II | 1.56 (1.11–2.18) | 0.010 | 1.26 (0.89–1.80) | 0.190 |
| III | 4.10 (2.02–8.33) | <0.001 | 2.66 (1.25–5.68) | 0.010 |
| Body mass index | 1.00 (0.95–1.05) | 0.930 | - | - |
| Pretreatment CEA | 1.00 (1.00–1.00) | 0.130 | - | - |
| Tumor location from the anal verge (cm) | ||||
| ≥12 | 1.00 (reference) | - | - | - |
| 8–12 | 1.17 (0.28–4.86) | 0.830 | - | - |
| 4–8 | 1.20 (0.30–4.91) | 0.790 | - | - |
| <4 | 1.21 (0.29–5.02) | 0.800 | - | - |
| Operative name | ||||
| Low anterior resection | 1.00 (reference) | - | 1.00 (reference) | - |
| Ultralow anterior resection | 1.51 (1.09–2.09) | 0.010 | 1.45 (1.04–2.03) | 0.030 |
| Abdominoperineal resection | 1.62 (0.91–2.87) | 0.100 | 1.42 (0.79–2.53) | 0.240 |
| Circumferential resection margin | ||||
| Negative | 1.00 (reference) | - | 1.00 (reference) | - |
| Positive | 3.59 (1.68–7.69) | 0.001 | 2.52 (1.15–5.53) | 0.020 |
| Tumor response to preoperative CRT | ||||
| pCR (ypT0N0) | 1.00 (reference) | - | 1.00 (reference) | - |
| Residual disease | 4.38 (2.23–8.58) | <0.001 | 4.33 (2.20–8.51) | <0.001 |
| Postoperative chemotherapy | ||||
| No | 1.00 (reference) | - | - | - |
| Yes | 1.05 (0.70–1.59) | 0.800 | - | - |
CI, confidence interval; ASA PS, American Society of Anesthesiologists physical status; CEA, carcinoembryonic antigen; CRT, chemoradiotherapy; pCR, pathologic complete response.