10213-GMC-16 A DECADE REVIEW: BEVACIZUMAB'S IMPACT ON GLIOBLASTOMA TREATMENT

Abstract OBJECTIVE This study aims to assess the efficacy of Bevacizumab (Bev) therapy, ten years after its initiation in treating glioblastoma patients at our department. METHODS Eighty-four patients treated with Bev from July 2013 to December 2022 were classified into three groups: the initial treatment group given the Stupp regimen with Bev (first-dose group), the group given the Stupp regimen plus Bev followed by tumor resection (neoadjuvant group), and those receiving the Stupp regimen post tumor resection (recurrence group). PET scans were conducted pre- and post- Bev therapy, and variations in Tumor-to-Normal ratio (TNR), Tumor-to-Blood ratio (TBR), and Metabolic Tumor Volume (MTV) were investigated. RESULTS The median Progression-Free Survival (PFS) and Overall Survival (OS) rates in the first, neoadjuvant, and recurrence groups were respectively (7.86, 14.27, 4.33) and (12.53, 21.57, 13.23) months. Notably, changes in MET and FMISO MTV in the first-treatment group, MET MTV and FMISO TBR changes in the recurrence group, and MET MTV change in the neoadjuvant group significantly influenced prognosis. In the recurrence group, patients who underwent total resection during initial treatment experienced a prolonged period of 25.9 months from initial treatment to the administration of Bev due to recurrence. Furthermore, cases where the FMISO TBR at recurrence was higher than at the initial treatment observed an extended median OS of 18.63 months upon administering Bev treatment at recurrence. CONCLUSION Bev neoadjuvant therapy demonstrated a significant correlation with enhanced PFS and OS outcomes, notably in patients subjected to total resection. In the context of recurrent disease, while the initiation of Bev administration was delayed, a distinct elevation in treatment effectiveness was observed in patients exhibiting an augmented FMISO TBR at the point of recurrence. The observed decreases in MET MTV and FMISO TBR emerge as robust predictors of the efficacy of Bev treatment.