Kaplan-Meier curves for survival using log-rank tests in patients with recurrent chordomas
| Explanatory Variables | Total No. | No. of Events | P Value |
|---|---|---|---|
| Univariate models | |||
| Age at first operation (yr) | .312 | ||
| Younger than 60 | 10 | 5 | |
| 60 or older | 6 | 2 | |
| No. of surgical resections at first MRI | .002 | ||
| 1 | 11 | 3 | |
| ≥2 | 5 | 4 | |
| Tumor volume | .957 | ||
| <3 × 103 × mm3 | 10 | 4 | |
| ≥3 × 103 × mm3 | 6 | 3 | |
| Histopathology | |||
| Chondroid chordoma | 5 | 1 | .346 |
| Classic chordoma | 11 | 6 | |
| Tumor location | .507 | ||
| Clivus | 11 | 5 | |
| Other sites | 5 (C = 1, L = 2, S = 1, other = 1) | 2 | |
| Adjuvant radiation therapy | .172 | ||
| None/unknown | 3 | 2 | |
| Done | 13 | 5 | |
| Mean ADC (for an aggressive tumor) | .006 | ||
| >1.494 × 10−3 × mm2/s | 10 | 2 | |
| ≤1.494 × 10−3 × mm2/s | 6 | 5 |
Note:—C indicates cervical spine; L, lumber spine; S, sacrum.