Table 2.
Summary results of Cox proportional hazard model of disease free and specific survival (DFS and DSS) from matching by site, stage, p16 status, and treatment using model-based adjustment for T and N stage, age and smoking status and allowing the number of controls per case to vary
| Parameter | DFS | DSS | ||||
|---|---|---|---|---|---|---|
| p value | Hazard ratio | 95 % Confidence interval for HR | p value | Hazard ratio | 95 % Confidence interval for HR | |
| Case versus Control | 0.012 | 2.21 | (1.19, 4.11) | 0.36 | 1.49 | (0.638, 3.48) |
| Age at diagnosis (per 5 year increase) | <.0001 | 1.17 | (1.10, 1.24) | 0.025 | 1.10 | (1.01, 1.19) |
| Smoker versus Nonsmoker | 0.0534 | 1.44 | (0.995, 2.08) | 0.55 | 0.868 | (0.546, 1.38) |
| T Stage (T3–T4 versus T1–T2) | 0.0025 | 1.57 | (1.17, 2.10) | 0.0002 | 2.01 | (1.40, 2.90) |
| N Stage (N2b–N3 versus N0–N2a) | 0.0892 | 1.31 | (0.959, 1.79) | 0.0014 | 1.90 | (1.28, 2.82) |
DFS Disease free survival, DSS Disease specific survival, HR Hazard ratio, values in bold are statistically significant