Abstract: PURPOSE: To determine if there is an association between the incidental radiation dose to the subventricular zone and survival in patients with glioblastoma multiforme treated with surgery, radiotherapy and temozolomide. METHODS AND MATERIALS: Sixty-five patients, treated between 2006 and 2015, were included in this retrospective study. The doses (75th percentile; p75) administered to the ipsilateral, contralateral and bilateral subventricular zone were compared to overall survival and progression-free survival using Cox proportional hazards models. Covariates included: age, sex, surgery, tumor location, and concomitant and adjuvant temozolomide. RESULTS: Median progression-free survival and overall survival were 11.5 +/- 9.96 and 18.8 +/- 18.5 months, respectively. The p75 doses to the ipsilateral, contralateral and bilateral subventrivular zone were, respectively, 57.30, 48.8, and 52.7 Gy. Patients who received a dose >/=48.8 Gy in the contralateral subventricular zone had better progression-free survival than those who received lower doses (HR 0.46; 95% CI 0.23-0.91 P = 0.028). This association was not found for overall survival (HR 0.60; 95% CI 0.30-1.22 P = 0.16). Administration of adjuvant temozolomide was significantly associated with improved progression-free survival (HR 0.19; 95% CI 0.09-0.41 P < 0.0001) and overall survival (HR 0.11; 95% CI 0.05-0.24 P = 0.001). In the subgroup of 46 patients whose O6-methylguanine-DNA methyltransferase gene promoter status was known, the methylation had no effect on either progression-free survival (P = 0.491) or overall survival (P = 0.203). CONCLUSION: High-dose radiation in the contralateral subventricular zone was associated with a significant improvement in progression-free survival but not overall survival in patients treated for glioblastoma multiforme.

Abstract: The optimal management of recurrent glioblastoma (GBM) has yet to be determined. We aim to assess the benefits of re-operation and salvage therapies (chemotherapy and/or re-irradiation) for recurrent GBM and to identify prognostic factors associated with better survival. All patients who underwent surgery for GBM between January 2005 and December 2012 followed by adjuvant radiotherapy, and who developed GBM recurrence on imaging were included in this retrospective study. Univariate and multivariate analysis was performed using Cox models in order to identify factors associated with overall survival (OS). One hundred and eighty patients treated to a dose of 60 Gy were diagnosed with recurrent GBM. At a median follow-up time of 6.2 months, the median survival (MS) from time of recurrence was 6.6 months. Sixty-nine patients underwent repeat surgery for recurrence based on imaging. To establish the benefits of repeat surgery and salvage therapies, 68 patients who underwent repeat surgery were matched to patients who did not based on extent of initial resection and presence of subventricular zone involvement at recurrence. MS for patients who underwent re-operation was 9.6 months, compared to 5.3 months for patients who did not have repeat surgery (p < 0.0001). Multivariate analysis in the matched pairs confirmed that repeat surgery with the addition of other salvage treatment can significantly affect patient outcome (HR 0.53). Re-operation with additional salvage therapies for recurrent GBM provides survival prolongation at the time of progression.

Abstract: Glioblastoma (GBM) remains one of the most fatal human malignancies due to its high angiogenic and infiltrative capacities. Even with optimal therapy including surgery, radiotherapy and temozolomide, it is essentially incurable. GBM is among the most neovascularised neoplasms and its malignant progression associates with striking neovascularisation, evidenced by vasoproliferation and endothelial cell hyperplasia. Targeting the pro-angiogenic pathways is therefore a promising anti-glioma strategy. Here we show that tivozanib, a pan-inhibitor of vascular endothelial growth factor (VEGF) receptors, inhibited proliferation of GBM cells through a G2/M cell cycle arrest via inhibition of polo-like kinase 1 (PLK1) signalling pathway and down-modulation of Aurora kinases A and B, cyclin B1 and CDC25C. Moreover, tivozanib decreased adhesive potential of these cells through reduction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Tivozanib diminished GBM cell invasion through impairing the proteolytic cascade of cathepsin B/urokinase-type plasminogen activator (uPA)/matrix metalloproteinase-2 (MMP-2). Combination of tivozanib with EGFR small molecule inhibitor gefitinib synergistically increased sensitivity to gefitinib. Altogether, these findings suggest that VEGFR blockade by tivozanib has potential anti-glioma effects in vitro. Further in vivo studies are warranted to explore the anti-tumour activity of tivozanib in combinatorial approaches in GBM.