Table 4.
DAG-guided multivariable Cox regression model analysis of causal effect of chemotherapy on OS and CSS.
| Variables | OS | CSS | ||
|---|---|---|---|---|
| HR (95% CI) | p | HR (95% CI) | p | |
| Chemotherapy | ||||
| Yes | Reference | Reference | ||
| No/unknown | 2.918 (1.75–4.868) | <0.001 | 2.747 (1.604–4.703) | <0.001 |
| Surgery | ||||
| Yes | Reference | Reference | ||
| No | 4.131 (1.971–8.659) | <0.001 | 4.258 (1.95–9.298) | <0.001 |
| Age (years) | 1.012 (0.998–1.025) | 0.092 | 1.005 (0.991–1.019) | 0.464 |
| Tumor size (mm) | 1.002 (1.000–1.004) | 0.031 | 1.002 (1.000–1.004) | 0.031 |
| Pathologic grade | ||||
| Grade I | Reference | Reference | ||
| Grade II | 0.582 (0.193–1.758) | 0.337 | 1.791 (0.213–15.045) | 0.592 |
| Grade III | 0.901 (0.334–2.433) | 0.838 | 3.400 (0.447–25.899) | 0.237 |
| Grade IV | 1.285 (0.471–3.51) | 0.625 | 4.624 (0.604–35.402) | 0.140 |
| T stage | ||||
| T1 | Reference | Reference | ||
| T2 | 1.596 (0.698–3.646) | 0.268 | 1.598 (0.62–4.119) | 0.332 |
| T3 | 1.778 (1.057–2.991) | 0.030 | 1.999 (1.123–3.559) | 0.019 |
| T4 | 1.253 (0.611–2.567) | 0.538 | 1.329 (0.612–2.888) | 0.472 |
| N stage | ||||
| N0 | Reference | Reference | ||
| N1 | 2.047 (1.232–3.401) | 0.006 | 2.069 (1.215–3.522) | 0.007 |
| N2 | 1.295 (0.771–2.178) | 0.329 | 1.419 (0.827–2.436) | 0.204 |
| M stage | ||||
| M0 | Reference | Reference | ||
| M1 | 4.621 (2.81–7.598) | <0.001 | 4.694 (2.781–7.923) | <0.001 |
CDC, collecting duct carcinoma; DAG, directed acyclic graphs; CI, confidence interval; HR, hazard ratio; OS, overall survival; CSS, cancer-specific survival.