Table VI.
Multivariate Cox regression analysis in patients <25 years of age with osteosarcoma between 1973 and 2012.
| Model 1 | Model 2 | |||
|---|---|---|---|---|
| Variables | HR (95% CI) | P-value | HR (95%CI) | P-value |
| Year of diagnosis | P<0.001 | aP<0.001 | ||
| 1973–1982 | Reference | Reference | ||
| 1983–1992 | 0.649 (0.500–0.841) | 0.001 | 0.657 (0.529–0.816) | aP<0.001 |
| 1993–2002 | 0.611 (0.484–0.771) | P<0.001 | 0.594 (0.491–0.719) | aP<0.001 |
| 2003–2012 | 0.528 (0.418–0.666) | P<0.001 | 0.507 (0.419–0.613) | aP<0.001 |
| Sex | 0.042 | aP<0.001 | ||
| Male | Reference | Reference | ||
| Female | 0.866 (0.754–0.995) | 0.042 | 0.805 (0.710–0.912) | aP<0.001 |
| Age at diagnosis (years) | 0.042 | 0.081 | ||
| 0–4 | Reference | Reference | ||
| 5–9 | 0.859 (0.518–1.423) | 0.554 | 0.837 (0.52–1.349) | 0.466 |
| 10–14 | 0.726 (0.448–1.176) | 0.193 | 0.716 (0.454–1.129) | 0.151 |
| 15–19 | 0.909 (0.561–1.471) | 0.697 | 0.832 (0.528–1.311) | 0.428 |
| 20–24 | 0.920 (0.558–1.516) | 0.743 | 0.902 (0.566–1.440) | 0.667 |
| Race | 0.452 | |||
| Caucasian | Reference | |||
| African descent | 1.123 (0.935–1.348) | 0.214 | ||
| Other | 1.043 (0.818–1.332) | 0.733 | ||
| CHSDA region | 0.003 | a0.035 | ||
| East | Reference | Reference | ||
| Northern Plains | 1.372 (1.101–1.711) | 0.005 | 1.190 (0.978–1.448) | 0.082 |
| Pacific Coast | 1.164 (0.978–1.385) | 0.088 | 1.133 (0.971–1.323) | 0.114 |
| Southwest | 1.515 (1.187–1.934) | 0.001 | 1.378 (1.108–1.715) | a0.004 |
| Rural or urban | 0.71 | |||
| Rural | Reference | |||
| Urban | 1.046 (0.824–1.328) | 0.71 | ||
| Stage | P<0.001 | aP<0.001 | ||
| Localized | Reference | Reference | ||
| Regional | 1.612 (1.360–1.911) | P<0.001 | 1.585 (1.360–1.848) | aP<0.001 |
| Distant | 4.036 (3.357–4.853) | P<0.001 | 3.899 (3.292–4.616) | aP<0.001 |
| Laterality | 0.944 | |||
| Right | Reference | |||
| Left | 0.995 (0.873–1.135) | 0.944 | ||
| Histologic type ICD-O-3 | P<0.001 | aP<0.001 | ||
| Osteosarcoma, NOS | Reference | Reference | ||
| Chondroblastic | 0.821 (0.669–1.008) | 0.060 | 0.869 (0.721–1.046) | 0.137 |
| Fibroblastic | 0.669 (0.464–0.965) | 0.032 | 0.779 (0.567–1.070) | 0.124 |
| Telangiectatic | 0.770 (0.538–1.102) | 0.154 | 0.782 (0.553–1.107) | 0.166 |
| Parosteal | 0.365 (0.218–0.614) | P<0.001 | 0.354 (0.218–0.576) | aP<0.001 |
| Primary site-labeled | P<0.001 | aP<0.001 | ||
| Upper limb | Reference | Reference | ||
| Lower limb | 0.737 (0.617–0.881) | 0.001 | 0.777 (0.654–0.923) | a0.004 |
| Skull and mandible | 0.668 (0.316–1.495) | 0.344 | 0.689 (0.494–0.960) | a0.028 |
| Vertebral and chest bones | 0.834 (0.487–1.429) | 0.509 | 0.982 (0.691–1.395) | 0.917 |
| Pelvic bones | 1.625 (1.157–2.281) | 0.005 | 1.612 (1.210–2.147) | a0.001 |
| Surgery | P<0.001 | aP<0.001 | ||
| Yes | Reference | Reference | ||
| No | 1.726 (1.434–2.077) | P<0.001 | 1.645 (1.391–1.946) | aP<0.001 |
| Radiation | P<0.001 | aP<0.001 | ||
| Yes | Reference | Reference | ||
| No | 0.600 (0.461–0.781) | P<0.001 | 0.548 (0.442–0.679) | aP<0.001 |
a
Statistically significant. P<0.05 was considered to indicate statistically significant difference. P-values were calculated by multivariate Cox regression analysis. Model 1 excluded grade, tumor size and surgery type, which had incomplete data in the univariate analysis. Model 2 further excluded race, rural or urban, and laterality, which had no significant difference in the univariate analysis. HR, hazard ratio; CI, confidence interval; n, number; ICD, International Classification of Disease; NOS, not otherwise specified; CHSDA, Contract Health Service Delivery Areas.