Lack of benefit of temozolomide for MGMT methylated patients with high vascular glioblastoma: a confirmatory study.

Abstract

Simple Summary: Despite the complete treatment with surgery, chemotherapy and radiotherapy, patients with glioblastoma have a devasting prognosis. Although the role of extending temozolomide treatment has been explored, the results are inconclusive. Recent evidence suggested that tumor vascularity may be a modulating factor in combination with MGMT methylation on the effect of temozolomide-based therapies, opening new possibilities for personalized treatments. Before proposing a prospective interventional clinical study, it is necessary to confirm the beneficial effect of the combined effect of MGMT methylation and moderate tumor vascularity. As well as the lack of benefit of temozolomide in patients with a highly vascular tumor. Abstract: In this study we evaluated the benefit on survival of the combination of MGMT methylation and moderate vascularity in glioblastoma using a retrospective dataset of 123 patients from a multicenter cohort. MRI processing and calculation of relative cerebral blood volume (rCBV), used to define moderate- and high-vascular groups, were performed with the automatic ONCOhabitats method. We assessed the previously proposed rCBV threshold (10.7) and the new calculated ones (9.1 and 9.8) to analyze the association with survival for different populations according to vascularity and MGMT methylation status. We found that patients included at the moderate-vascular group had longer survival when MGMT is methylated (significant median survival difference of 174 days, p = 0.0129*). However, we did not find significant differences depending on the MGMT methylation status for the high-vascular group (p = 0.9119). In addition, we investigated the combined correlation of MGMT methylation status and rCBV with the prognostic effect of the number of temozolomide cycles, and only significant results were found for the moderate-vascular group. In conclusion, there is a lack of benefit of temozolomide for MGMT methylated patients with high vascular glioblastomas. Preliminary results suggest that patients with moderate vascularity and methylated MGMT would benefit more from prolonged adjuvant chemotherapy.