Table 5.
DAG-guided multivariable Cox regression model analysis of causal effect of radiotherapy on OS and CSS.
| Variables | OS | CSS | ||
|---|---|---|---|---|
| HR (95% CI) | p | HR (95% CI) | p | |
| Radiotherapy | ||||
| Yes | Reference | Reference | ||
| No/unknown | 1.139 (0.6133–2.115) | 0.68 | 1.292 (0.667–2.501) | 0.448 |
| Surgery | ||||
| Yes | Reference | Reference | ||
| No | 3.530 (1.571–7.936) | 0.002 | 3.881 (1.654–9.105) | 0.002 |
| Age (years) | 1.016 (1.003–1.029) | 0.02 | 1.010 (0.996–1.023) | 0.173 |
| Tumor size (mm) | 1.003 (1.001–1.005) | 0.0115 | 1.003 (1.000–1.005) | 0.015 |
| Pathologic grade | ||||
| Grade I | Reference | Reference | ||
| Grade II | 0.589 (0.196–1.765) | 0.344 | 1.816 (0.217–15.176) | 0.582 |
| Grade III | 0.953 (0.354–2.566) | 0.923 | 3.579 (0.470–27.227) | 0.218 |
| Grade IV | 1.132 (0.414–3.090) | 0.81 | 4.136 (0.540–31.667) | 0.172 |
| T stage | ||||
| T1 | Reference | Reference | ||
| T2 | 1.411 (0.623–3.194) | 0.409 | 1.412 (0.554–3.603) | 0.470 |
| T3 | 1.529 (0.908–2.573) | 0.11 | 1.734 (0.976–3.082) | 0.061 |
| T4 | 1.155 (0.552–2.417) | 0.703 | 1.245 (0.563–2.756) | 0.589 |
| N stage | ||||
| N0 | Reference | Reference | ||
| N1 | 1.476 (0.907–2.402) | 0.117 | 1.522 (0.911–2.544) | 0.109 |
| N2 | 1.154 (0.690–1.930) | 0.585 | 1.261 (0.740–2.152) | 0.394 |
| M stage | ||||
| M0 | Reference | Reference | ||
| M1 | 2.813 (1.828–4.329) | <0.001 | 2.934 (1.870–4.603) | <0.001 |
CDC, collecting duct carcinoma; DAG, directed acyclic graphs; CI, confidence interval; HR, hazard ratio; OS, overall survival; CSS, cancer-specific survival.