NIMG-06. OUR THERAPEUTIC STRATEGIES FOR GLIOBLASTOMA: INTRAOPERATIVE SUPPORT SYSTEMS [INTRAOPERATIVE MRI, PET, 5-AMINOLEVULINIC ACID (5-ALA)] AND NEOADJUVANT CHEMOTHERAPY

OBJECTIVE Neuronavigation systems with magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging (methionine [MET], fluorothymidine [FLT], and fluoromisonidazole [FMISO]) are routinely used in glioblastoma surgery. Residual tumor identified using intraoperative MRI (IoMRI) or 5-aminolevulinic acid (5-ALA) fluorescence is removed. Neoadjuvant bevacizumab therapy is offered to patients with low Karnovsky performance status (KPS) or with tumors in eloquent regions. We evaluated the usefulness of neoadjuvant bevacizumab therapy. METHODS Twelve patients with glioblastoma with low KPS or tumors in eloquent regions on multiple PET and IoMRI evaluations were enrolled between January 2016 and April 2019. Six had received neoadjuvant bevacizumab before surgery; six had not. Postsurgical 5-ALA fluorescence (strong, vague, and none) tumor extraction rate, residual volume on MRI and PET imaging, and prognosis in the patients with and without bevacizumab were compared. RESULTS In patients with bevacizumab adjuvant therapy, the KPS scores immediately prior to surgery were 90 in 3 cases, 80 in 2, and 70 in 1. The scores in patients without bevacizumab were 50 in 2 and 40 in 4. The 5-ALA fluorescence in patients with bevacizumab was vague in one and none in five. Vague fluorescence was noted in all six patients without bevacizumab. Tumor extraction rates in patients with vs. those without bevacizumab were 97.6% vs. 91.5% by T1-Gd, 95.4% vs. 99.9% by MET, 96.2% vs. 90.2% by FLT, and 97% vs. 92% by FMISO. Corresponding residual volumes (ml) were (0.6 vs. 1.7) for T1-Gd, 1.2 vs. 2.9 for MET, 1.0 vs. 2.1 for FLT, and 0.5 vs. 1.1 for. FLT. Median progression free survival (PFS) was 10.1 vs. 4.9 months; median overall survival (OS) was 15.7 vs. 13.3 months. CONCLUSIONS Neoadjuvant bevacizumab therapy improved KPS at the time of surgery, increased extraction rate, reduced residual tumor volume, and improved PFS and OS prognosis.