Table 4. Univariate analysis for survival.
| Risk factor | 1-year PFS (%) | p value | 1-year OS (%) | p value |
|---|---|---|---|---|
| Initial MGMT methylation | 0.950 | 0.088 | ||
| (+) | 42.9 | 85.7 | ||
| (-) | 46.0 | 32.6 | ||
| Initial Ki-67 | 0.630 | 0.388 | ||
| <30% | 58.9 | 76.2 | ||
| ≥30% | 15.0 | 57.9 | ||
| Recurrence Ki-67 | 0.748 | 0.349 | ||
| <30% | 35.0 | 100.0 | ||
| ≥30% | 28.6 | 71.4 | ||
| Interval between initial CCRT-first recurrence | 0.713 | 0.927 | ||
| ≥7 mo | 36.9 | 63.0 | ||
| <7 mo | 23.1 | 71.9 | ||
| Karnofsky performance status | 0.425 | 0.281 | ||
| ≥70 | 36.7 | 75.0 | ||
| <70 | 24.3 | 57.9 | ||
| Recurrent tumor size | 0.903 | 0.899 | ||
| <5 cm | 33.0 | 62.5 | ||
| ≥5 cm | 32.0 | 69.7 | ||
| Recurrence location | 0.188 | 0.013* | ||
| In-field | 34.6 | 71.9 | ||
| Out-field/In- and out-field | 30.0 | 46.7 | ||
| Surgical resection | 0.718 | 0.01* | ||
| Yes | 34.3 | 86.7 | ||
| No | 34.3 | 30.6 | ||
| Surgical resection extent | 0.118 | 0.071 | ||
| GTR or NTR | 40.0 | 90.0 | ||
| STR | 25.0 | 80.0 | ||
| Re-irradiation at first recurrence | 0.327 | 0.063 | ||
| Yes | 27.2 | 57.7 | ||
| No | 60.0 | 100.0 | ||
| Re-irradiation methods | 0.846 | 0.474 | ||
| SRS/FSRS | 28.9 | 59.7 | ||
| HSRT | 34.3 | 71.7 | ||
| Re-irradiation total dose | 0.302 | 0.787 | ||
| ≥50 Gy | 29.2 | 68.6 | ||
| <50 Gy | 32.6 | 65.8 | ||
| Chemotherapy | 0.874 | 0.916 | ||
| Yes | 26.5 | 60.1 | ||
| No | 43.2 | 74.0 |
*p<0.05. PFS, progression-free survival; OS, overall survival; MGMT, O6-methylguanine-DNA methyltransferase; CCRT, concurrent chemoradiotherapy; GTR, gross total resection; NTR, near-total resection; STR, subtotal resection; SRS, stereotactic radiosurgery; FSRS, fractionated stereotactic radiosurgery; HSRT, hypo-fractionated stereotactic radiotherapy