Table 3. Univariate analysis of the 5-year local control and overall survival.
| #patients | 5-year OS, % | p-value | 5-year LC, % | p-value | |
|---|---|---|---|---|---|
| Total #patients | 26 | 42% | 63% | ||
| Age | |||||
| <16 | 12 | 42% | 0.61 | 62% | 0.96 |
| ≥16 | 14 | 42% | 65% | ||
| Sex | |||||
| Male | 18 | 50% | 0.33 | 67% | 0.74 |
| Female | 8 | 25% | 57% | ||
| Performance status | |||||
| 1 | 19 | 47% | 0.65 | 63% | 0.94 |
| 2 | 7 | 29% | 64% | ||
| Pathologic subtype | |||||
| Osteoblastic | 13 | 61% | 0.11 | 79% | 0.09 |
| Others | 13 | 23% | 45% | ||
| Tumor location | |||||
| Pelvis | 24 | 41% | 0.84 | 61% | 0.36 |
| Others | 2 | 50% | 100% | ||
| Tumor status | |||||
| Primarya | 20 | 44% | 0.48 | 61% | 0.55 |
| Others | 6 | 33% | 83% | ||
| Tumor status | |||||
| Non-metastatic | 23 | 43% | 0.61 | 60% | 0.33 |
| Metastatic | 3 | 33% | 100% | ||
| Target volume (cm3) | |||||
| <452 | 13 | 54% | 0.14 | 81% | 0.07 |
| ≥452 | 13 | 29% | 38% | ||
| Largest tumor diameter | |||||
| ≤9.5 cm | 14 | 64% | 0.0013c | 75% | 0.03c |
| >9.5 cm | 12 | 13% | 45% | ||
| Response to chemo | |||||
| SD + PR | 12 | 48% | 0.07 | 65% | 0.29 |
| Othersb | 11 | 18% | 36% | ||
| Total CIRT dose (Gy RBE) | |||||
| ≥70.4 | 21 | 37% | 0.72 | 55% | 0.10 |
| <70.4 | 5 | 60% | 100% |
Abbreviations: #number; OS, overall survival; LC, local control; SD, stable disease; PR, partial response; CIRT, carbon ion radiotherapy; Gy RBE, Gray Relative Biological Effectiveness.
aexcluding locally recurrent (1) and radiation-induced (2) cases.
bOthers include progressive disease and incomplete chemotherapy regimen; excluding unknown response.
cdenotes statistical significance.