Table 3.
Univariate and multivariate analyses for overall survival
| Characteristic | No. | Median survival (mo) | p-valuea) (univariate) | p-valueb) (multivariate) |
|---|---|---|---|---|
| Sex | ||||
| Male | 8 | 28.4 | 0.601 | 0.204 |
| Female | 25 | 23.1 | ||
| Age at primary radiotherapy, median (yr) | ||||
| ≤ 44 | 17 | 34.9 | 0.886 | - |
| > 44 | 16 | 23.1 | ||
| Age at diagnosis of RIS, median (yr) | ||||
| ≤ 55 | 18 | 115.2 | 0.218 | 0.010c) |
| > 55 | 15 | 23.1 | ||
| Latency, median | ||||
| ≤ 12 | 16 | 115.2 | 0.233 | 0.176 |
| > 12 | 17 | 23.3 | ||
| Chemotherapy for primary cancer | ||||
| Yes | 21 | 34.9 | 0.704 | - |
| No | 12 | 28.4 | ||
| RIS location | ||||
| Trunk | 25 | 34.9 | 0.613 | 0.865 |
| Head and neck | 8 | 14.8 | ||
| RIS histology | ||||
| MFH | 11 | 124.0 | 0.121 | 0.376 |
| Osteosarcoma | 12 | 23.3 | ||
| Others | 10 | 14.8 | ||
| Tumor size (cm) | ||||
| ≤ 5 | 19 | 34.9 | 0.858 | 0.284 |
| > 5 | 14 | 23.3 | ||
| Tumor depth | ||||
| Deep | 27 | 22.2 | 0.980 | 0.320 |
| Superficial | 6 | 34.9 | ||
| Treatment | ||||
| Curative | 19 | 115.2 | 0.001 | 0.001c) |
| Palliation | 14 | 8.0 |
RIS, radiation induced sarcoma; MFH, malignant histiocytoma.
a)
Log-rank test,
b)
Cox regression analysis,
c)
Statistically significant.