Univariate analysis of factors associated with malignant transformationa
| Factors | Malignant Transformation | P Value | OR | 95% CI | |
|---|---|---|---|---|---|
| No | Yes | ||||
| Sex | .85 | 0.9 | 0.39–2.15 | ||
| Male | 28 | 35 | |||
| Female | 14 | 19 | |||
| Age (yr) | 49.1 ± 12.3 | 44.2 ± 12.6 | .058 | NA | –0.17–10.1 |
| KPS | 88.1 ± 11.9 | 90.7 ± 8.2 | .202 | NA | –6.73–1.44 |
| Histologic subtype | .604 | NA | NA | ||
| Diffuse astrocytoma | 12 | 18 | |||
| Oligoastrocytoma | 14 | 13 | |||
| Oligodendroglioma | 16 | 23 | |||
| IDH1 mutation | .525 | 1.7 | 0.31–9.67 | ||
| Yes | 25 | 36 | |||
| No | 2 | 5 | |||
| Mean disease duration (yr) | 6.9 ± 5.1 | 7.1 ± 5.4 | .818 | NA | –2.42–1.92 |
| Baseline residual tumor | .044 | 3.7 | 0.97–14.15 | ||
| Yes | 39 | 42 | |||
| No | 3 | 12 | |||
| RT | .037 | 3.1 | 1.03–9.37 | ||
| Yes | 37 | 38 | |||
| No | 5 | 16 | |||
| Post-RT duration (mo) | 59.5 ± 48.7 | 75.6 ± 54.5 | .182 | NA | –39.9–7.71 |
| Chemotherapy | .800 | NA | NA | ||
| None | 32 | 39 | |||
| Carmustine implant | 3 | 6 | |||
| Temozolomide | 7 | 9 | |||
| Whole-tumor size (cm2) | 10.8 ± 11.1 | 17.1 ± 11.1 | .007 | NA | –10.8 to −1.7 |
| Contrast-enhancement size (cm2) | 6.1 ± 6.6 | 12.3 ± 11.1 | .001 | NA | –10.7 to −2.8 |
| Cho/Cr | 3.31 ± 4.26 | 5.60 ± 4.61 | .015 | NA | –4.1 to −0.5 |
| NAA/Cho | 0.41 ± 0.28 | 0.10 ± 0.07 | <.001 | NA | 0.22–0.38 |
| NAA/Cr | 1.02 ± 1.19 | 0.58 ± 0.78 | .033 | NA | 0.04–0.84 |
| Lac/Cr | 0.43 ± 1.41 | 0.77 ± 1.62 | .285 | NA | –0.96–0.28 |
Note:—NA indicates not applicable; Lac, lactate; RT, radiation therapy; KPS, Karnofsky Performance Scale.
↵a Data are mean ± SD for age, KPS, disease duration, post-RT duration, whole-tumor size, contrast enhancement size, and MR spectroscopy metabolite ratios.