Table 3. Cox regression model for rectal adenocarcinoma patients stratified by radiation therapy (N = 22,610). Data indicated as hazard ratios (95% confidence intervals).
| Characteristic | No XRT (N = 8,939) | Preoperative XRT (N = 2,818) | Postoperative XRT (N = 5,954) | Stage IV (N = 4,899) |
|---|---|---|---|---|
| Age (years) | ||||
| <50 (ref) | 1 | 1 | 1 | 1 |
| 50–59 | 1.21(0.99–1.48) | 1.20(0.97–1.49) | 1.19(1.04–1.37) | 1.01(0.91–1.12) |
| 60–69 | 1.45(1.21–1.74) | 1.33(1.08–1.63) | 1.42(1.24–1.62) | 1.20(1.08–1.32) |
| 70–79 | 1.93(1.62–2.30) | 1.96(1.59–2.42) | 1.74(1.52–1.99) | 1.43(1.29–1.58) |
| 80+ | 2.82(2.35–3.39) | 2.24(1.61–3.11) | 2.40(1.98–2.90) | 1.55(1.37–1.74) |
| Gender | ||||
| Male (ref) | 1 | 1 | 1 | 1 |
| Female | 0.86(0.79–0.93) | 1.00(0.87–1.15) | 0.92(0.84–1.00) | 1.01(0.94–1.07) |
| Ethnicity | ||||
| White(ref) | 1 | 1 | 1 | 1 |
| Black | 1.33(1.15–1.55) | 1.72(1.33–2.22) | 1.30(1.10–1.52) | 1.18(1.06–1.31) |
| Other | 0.93(0.81–1.07) | 1.21(0.96–1.52) | 0.91(0.79–1.04) | 0.90(0.81–1.00) |
| Tumor Grade | ||||
| Low (ref) | 1 | 1 | 1 | 1 |
| High | 1.31(1.18–1.46) | 1.68(1.44–1.97) | 1.43(0.31–1.57) | 1.50(1.39–1.61) |
| Unknown | 1.01(0.82–1.24) | 0.93(0.70–1.23) | 1.29(1.05–1.60) | 1.07(0.98–1.17) |
| Surgery | ||||
| Local excision (ref) | 1 | 1 | 1 | 1 |
| Radical surgery | 1.07(0.64–1.79) | 0.54(0.17–1.70) | 0.78(0.47–1.30) | 0.74(0.62–0.89) |
| No surgery | - | - | - | 1.66(1.38–1.99) |
| AJCC stage | ||||
| I (ref) | 1 | 1 | 1 | - |
| IIA | 2.29(2.04–2.56) | 1.84(1.44–2.35) | 1.34(1.02–1.75) | - |
| IIB | 3.86(3.08–4.83) | 3.38(2.43–4.69) | 2.62(1.90–3.61) | - |
| IIIA | 2.37(1.94–2.91) | 1.77(1.16–2.71) | 1.21(0.90–1.63) | - |
| IIIB | 5.13(4.55–5.79) | 4.26(3.35–5.44) | 2.51(1.93–3.27) | - |
| IIIC | 8.32(7.35–9.40) | 7.00(5.45–8.99) | 4.19(3.22–5.44) | - |
| IV | - | - | - | - |
XRT, radiation therapy;AJCC, American Joint Commission on Cancer Staging Manual (6th ed.).