Table 2.
Adjusted Mortality Data Associated with Primary Tumor Resection Among Stage IV Colon Cancer Patients, by Landmark Status (No-PTR (ref) vs PTR). (Abbreviations: PRT, primary tumor resection; IPTW, propensity score inverse probability of treatment weighting; CI, confidence interval)
| Risk-Adjustment Method | Total Cohort (N=15154) | Landmark Subgroup (N=6735) |
|---|---|---|
| Hazard ratio (95% CI) | Hazard ratio (95% CI) | |
| Unadjusted Cox regression | 0.459(0.443, 0.475) | 0.630(0.593,0.669) |
| Adjusted Cox regression a | 0.453(0.435, 0.471) | 0.600(0.557,0.645) |
| Without chemotherapy | 0.466(0.439, 0.495) | 0.628(0.533,0.740) |
| With chemotherapy | 0.456(0.431, 0.483) | 0.582(0.536,0.632) |
| Hazard ratio (95% CI) | Hazard ratio (95% CI) | |
|---|---|---|
| Propensity score-unadjusted Cox model using IPTW | 0.519(0.493, 0.547) | 0.605(0.555, 0.659) |
| Propensity score-adjusted Cox model using IPTW a | 0.461(0.436, 0.488) | 0.591(0.544, 0.643) |
| Without chemotherapy | 0.478(0.443, 0.516) | 0.596(0.498, 0.713) |
| With chemotherapy | 0.453(0.423, 0.486) | 0.567(0.516, 0.623) |
| Adjusted Relative Mortality Rate (95% CI) | Adjusted Relative Mortality Rate (95% CI) | |
|---|---|---|
| Instrumental variable-adjusted a 3-year mortality | 0.913(0.865, 0.959) | 0.972(0.879, 1.063) |
| Without chemotherapy | 0.946(0.893, 0.999) | 1.019(0.820, 1.221) |
| With chemotherapy | 0.886(0.812, 0.962) | 0.948(0.844, 1.052) |
a
Adjusted for the following variables based on their availability in the NCDB and their clinical significance: age at diagnosis, gender, race, year of diagnosis, tumor histology, tumor grade, tumor location, chemotherapy, insurance status, median income quartile, proportion without high school degree by ZIP code, population density of residence by ZIP code, facility location, facility type, and comorbidity score