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Background Preoperative neoadjuvant bevacizumab (neoBev) reduces enhancement and perifocal edema by inhibition of angiogenesis and vascular permeability for glioblastoma (GBM). The aim of this study was to investigate safety and efficacy of neoBev for newly diagnosed GBM through an exploratory prospective multi-center study. METHODS & PATIENTS 15 patients with newly diagnosed GBM were enrolled in the present study. Eligibility was a patient with a brain tumor representing with ring-shaped enhancement and perifocal edema on magnetic resonance imaging (MRI). Based on neuroimage of typical GBM, neoBev and temozolomide (TMZ) were administered prior to craniotomy. Two weeks after neoBev, the tumor volume on T1-weighted gadolinium enhancement (T1Gd) and fluid attenuated inversion recovery (FLAIR) were assessed. Three to four weeks after neoBev and TMZ administration, patients underwent surgical resection. The primary endpoint was feasibility and safety, and the secondary endpoint was efficacy. Adverse events including systemic toxicity and wound healing delay during radiation (RT), TMZ, and Bev combined therapy were carefully monitored throughout clinical course including extent of resection. RESULTS Average of tumor regression rate two weeks after neoBev on T1Gd and FLAIR were 37.0% and 54.0%, respectively. Cerebral blood flow and cerebral blood volume were reduced after neoBev. Patients underwent surgical resection safely without excess blood loss due to less vascular and less degree of brain swelling. Two patients underwent awake surgery without any complications. Postoperative MRI showed that the all tumors were totally removed except one with multiple invasive tumors. Histological diagnosis of all patients was GBM, IDH-1 wild-type. Postoperative course was uneventful without neurological deficit and adverse effects except one postoperative hematoma in the resection cavity and one wound infection due to wound dehiscence. CONCLUSION Preoperative neoBev for newly diagnosed GBM might contribute to safe surgery. Clinical outcome of this therapeutics is now currently under investigation.

Background: Previously we reported that bevacizumab (Bev) produces tumor oxygenation with immunosupportive tumor microenvironment (TME) and inhibition of stemness. To confirm whether those effects might contribute prolongation of clinical outcome, in the present study paired samples from same patients with newly diagnosed GBM who received Bev during its effectiveness and refractoriness were investigated by immunohistochemistry. Methods: Eighteen samples from 9 patients with newly diagnosed GBM who received preoperative neoadjuvant Bev (neoBev) followed by surgical operation and chemoradiotherapy in addition to salvage surgery after recurrence were investigated. Expressions of FOXM1, HIF-1, and CD163 were evaluated by immunohistochemistry. Overall survial (OS) were analyzed with the present cohort divided into two groups between good and poor responder (GR and PR, respectively) of Bev defined as tumor regression rate judged by T1 gadolinium enhancement (T1Gd) and fluid attenuated inversion recovery (FLAIR) images. Results: In the group of good responder of T1Gd (T1Gd-GR; defined as >38% of regression rate after neoBev), OS was prolonged compared with T1Gd-PR along with inhibition of FOXM1 expression and HIF-1a. In contrast, in the group of good responder of FLAIR (FLAIR-GR; defined as >54% of regression rate after neoBev), there were no significant differences of OS and FOXM1 expression between GR and PR. HIF-1a expression tended to be elevated in T1Gd-PR of initial tumors, T1Gd-GR of recurrent tumors, and FLAIR-PR of both initial and recurrent tumors.Conclusion: T1Gd-GR after neoBev might attribute to inhibition of FOXM1 and oxygenation. Bev might provide tumor oxygenation, leading to inhibition of stemness and M2 TAM infiltration during its effectiveness. These results suggested that Bev combined with immunotherapy for newly diagnosed GBM might provide clinical benefits including inhibition of stemness and induction of immunosupportive TME, when tumor volume assessed by T1 Gd. was significantly decreased following neoBev.