Table 1. Multivariate Analysis of PFS and OS on the Basis of KRAS-Variant Status.
| Variable | PFS (n = 179 Events) |
OS (n = 134 Events) |
||
|---|---|---|---|---|
| HR (95% CI)a | P Value | HR (95% CI)a | P Value | |
| KRAS-variant | ||||
| Earlyb | 0.42 (0.14-1.26) | .12 | 0.27 (0.06-1.21) | .09 |
| Late | 1.22 (0.53-2.80) | .64 | 1.47 (0.53-4.03) | .46 |
| Nonvariant | ||||
| Earlyb | 1.20 (0.80-1.80) | .39 | 0.89 (0.56-1.41) | .62 |
| Late | 0.79 (0.47-1.33) | .38 | 0.81 (0.45-1.48) | .49 |
Abbreviations: HR, hazard ratio; OS, overall survival; PFS, progression-free survival.
a
The HRs were estimated from Cox proportional hazards models, including treatment (cetuximab vs no cetuximab), treatment × PFS and OS time interaction, KRAS (variant vs nonvariant), treatment × KRAS interaction, treatment × PFS and OS time × KRAS interaction, age, Zubrod performance status (1 vs 0), primary site (oropharynx vs others), T stage (T4 vs T2-3), and N stage (N2b-3 vs N0-2a).
b
First year for PFS and first 2 years for OS.