Table 3.
Cox regression models for overall survival in patients with extraskeletal osteosarcoma in the unmatched cohort.
| Characteristic | Unadjusted* (unmatched cohort) | Model 1** (unmatched cohort) | Model 2*** (unmatched cohort) | ||||
|---|---|---|---|---|---|---|---|
| HR (95% CI) | P value | HR (95% CI) | P value | HR (95% CI) | P value | ||
| Chemotherapy | No | Reference | NA | Reference | NA | Reference | NA |
| Yes | 0.774 (0.583–1.027) | 0.076 | 0.764 (0.555–1.051) | 0.098 | 0.723 (0.589–1.011) | 0.055 | |
| Age(year) | <60 | Reference | NA | Reference | NA | Reference | NA |
| ≥60 | 1.848 (1.384–2.468) | <0.001 | 2.095 (1.503–2.922) | <0.001 | 2.165 (1.521–3.082) | <0.001 | |
| Gender | Male | Reference | NA | Reference | NA | ||
| Female | 0.953 (0.718–1.266) | 0.742 | 0.815 (0.576–1.155) | 0.251 | |||
| Race | White | Reference | NA | Reference | NA | Reference | NA |
| Black | 0.804 (0.505–1.281) | 0.359 | 0.941 (0.572–1.546) | 0.809 | 1.011 (0.612–1.668) | 0.968 | |
| Other | 0.578 (0.304–1.100) | 0.095 | 0.738 (0.374–1.456) | 0.381 | 0.678 (0.339–1.356) | 0.272 | |
| Insurance type | Insured | Reference | NA | Reference | NA | ||
| Any medicaid | 1.244 (0.682–2.269) | 0.477 | 1.166 (0.591–2.307) | 0.659 | |||
| Unknown | 0.786 (0.568–1.087) | 0.146 | 1.499 (0.737–3.045) | 0.264 | |||
| Marital status | Single | Reference | NA | Reference | NA | Reference | NA |
| Widowed/divorced | 1.945 (1.226–3.084) | 0.005 | 1.501 (0.902–2.496) | 0.118 | 1.631 (0.968–2.745) | 0.066 | |
| Married | 1.416 (0.926–2.164) | 0.108 | 1.196 (0.751–1.906) | 0.451 | 1.186 (0.733–1.918) | 0.487 | |
| Unknown | 1.705 (0.655–4.439) | 0.274 | 2.104 (0.789–5.612) | 0.137 | 1.657 (0.589–4.659) | 0.338 | |
| Year of diagnosis | 1976 to 1985 | Reference | NA | Reference | NA | ||
| 1986 to 1995 | 1.165 (0.621–2.188) | 0.634 | 1.476 (0.751–2.905) | 0.261 | |||
| 1996 to 2005 | 0.952 (0.535–1.692) | 0.867 | 1.032 (0.553–1.927) | 0.921 | |||
| 2006 to 2016 | 1.319 (0.745–2.338) | 0.342 | 2.195 (0.911–5.296) | 0.081 | |||
| Primary site | Extremity | Reference | NA | Reference | NA | Reference | NA |
| Trunk | 1.834 (1.287–2.611) | <0.001 | 2.181 (1.488–3.197) | <0.001 | 2.437 (1.632–3.638) | <0.001 | |
| Visceral | 3.642 (2.489–5.329) | <0.001 | 2.964 (1.951–4.505) | <0.001 | 3.337 (2.136–5.211) | <0.001 | |
| Other | 1.133 (0.703–1.826) | 0.609 | 1.382 (0.810–2.359) | 0.235 | 1.442 (0.833–2.495) | 0.191 | |
| Grade | Grade I/II | Reference | NA | Reference | NA | Reference | NA |
| Grade III/IV | 2.225 (1.088–4.553) | 0.029 | 2.102 (0.997–4.435) | 0.051 | 1.907 (0.894–4.068) | 0.095 | |
| Unknown | 2.652 (1.266–5.555) | 0.010 | 1.706 (0.793–3.669) | 0.172 | 1.768 (0.813–3.842) | 0.151 | |
| Stage | Localized | Reference | NA | Reference | NA | Reference | NA |
| Regional | 1.801 (1.284–2.525) | <0.001 | 1.718 (1.202–2.456) | 0.003 | 1.791 (1.234–2.601) | 0.002 | |
| Distant | 3.495 (2.366–5.163) | <0.001 | 2.456 (1.563–3.859) | <0.001 | 2.661 (1.644–4.308) | <0.001 | |
| Unstaged | 2.806 (1.550–5.080) | <0.001 | 1.523 (0.795–2.917) | 0.205 | 1.588 (0.801–3.151) | 0.186 | |
| Tumor size (mm) | <73 | Reference | NA | Reference | NA | Reference | NA |
| ≥73 | 2.684 (1.993–3.613) | <0.001 | 3.374 (2.420–4.704) | <0.001 | 3.399 (2.423–4.769) | <0.001 | |
| Radiation | Yes | Reference | NA | Reference | NA | ||
| No | 1.116 (0.799–1.560) | 0.519 | 0.664 (0.452–0.976) | 0.037 | |||
| Surgery | Yes | Reference | NA | Reference | NA | Reference | NA |
| No | 2.553 (1.743–3.740) | <0.001 | 2.302 (1.492–3.554) | <0.001 | 2.434 (1.561–3.796) | <0.001 | |
CI – confidence interval; NA – not applicable; HR – hazard ratio; mm – millimeter.
*
Univariable Cox regression analysis in the unmatched cohort.
**
Multivariable Cox regression adjusted for chemotherapy, age, race, marital status, primary site, grade, stage, tumor size and surgery in the unmatched cohort.
***
Multivariable Cox regression adjusted for all characteristics in the study in the unmatched cohort.