Addition of MR imaging features and genetic biomarkers strengthens glioblastoma survival prediction in TCGA patients.

PURPOSE: The purpose of our study was to assess whether a model combining clinical factors, MR imaging features, and genomics would better predict overall survival of patients with glioblastoma (GBM) than either individual data type. METHODS: The study was conducted leveraging The Cancer Genome Atlas (TCGA) effort supported by the National Institutes of Health. Six neuroradiologists reviewed MRI images from The Cancer Imaging Archive (http://cancerimagingarchive.net) of 102 GBM patients using the VASARI scoring system. The patients' clinical and genetic data were obtained from the TCGA website (http://www.cancergenome.nih.gov/). Patient outcome was measured in terms of overall survival time. The association between different categories of biomarkers and survival was evaluated using Cox analysis. RESULTS: The features that were significantly associated with survival were: (1) clinical factors: chemotherapy; (2) imaging: proportion of tumor contrast enhancement on MRI; and (3) genomics: HRAS copy number variation. The combination of these three biomarkers resulted in an incremental increase in the strength of prediction of survival, with the model that included clinical, imaging, and genetic variables having the highest predictive accuracy (area under the curve 0.679±0.068, Akaike's information criterion 566.7, P<0.001). CONCLUSION: A combination of clinical factors, imaging features, and HRAS copy number variation best predicts survival of patients with GBM.

Subependymal seeding of low-grade oligodendroglial neoplasms: a case series.

The CSF dissemination of low-grade glial tumors is a known albeit rare entity. Few cases have been reported in the literature. We describe a unique series of six patients with supratentorial low-grade gliomas who presented to our institution at ages 20-41 years, and developed signal abnormality along the margin of the fourth ventricle without enhancement at variable times during their disease course (0 to 95 months). MR spectroscopy and perfusion-weighted imaging through the region of abnormality in two of these patients were consistent with a low-grade glial tumor. We hypothesize that this finding represents dissemination of the supratentorial low-grade glioma along the ventricular ependyma or through the ventricular CSF. Although the small size of our series does not allow us to draw statistically significant conclusions, this abnormality correlates with progression of the supratentorial disease with or without features of a higher grade malignancy. Additional variables that were present in all six patients include the presence of an oligodendroglial component within the supratentorial tumor, mutated IDH1, and the supratentorial tumor contacting the ventricular margin. All six patients were males.