Article ID: jslsm-46_0027
Recurrence of glioblastoma is often seen at the margins of the resection space and is attributed to the involvement of residual tumor cells, particularly highly infiltrative glioma stem cells (GSCs), in the same area. Although recent reports indicate that glioblastoma requires supra-total resection of the area surrounding the T1 gadolinium-enhancing lesion, it remains to be determined whether GSCs are present in this area. Therefore, if the location of GSCs can be accurately identified preoperatively and intraoperatively, tumor removal including GSCs, i.e., “true supra-total resection”, would be possible. Therefore, the development of new surgical assistance technology is needed. We evaluated 108 glioblastoma surgery cases from April 2017 to March 2025, and reported on the usefulness of the methionine accumulation rate assessment using 11C-Met-positron emission tomography (PET) and metabolic analysis using magnetic resonance spectroscopy (MRS) utilizing the LC-model as a method to identify the residual GSCs in the tumor margins. More recently, in addition to the conventional 5-aminolevulinic acid photodynamic diagnosis (ALA-PDD), we have quantitatively evaluated the 5-ALA fluorescence intensity at the margin of the resection cavity by spectroscopy using purple laser light to identify the extent of the GSC invasion intraoperatively in real time. We established three parameters for determining the extent of the resection: Tumor-to-normal contralateral ratio (TNR) >1.4 on 11C-Met-PET, lactate/creatin ratio >0.66 on MRS, and fluorescence intensity >1,000 a.u. on intraoperative 5-ALA-PDD quantitative assessment. In our current presentation, we discuss the advantages and disadvantages of tumor resection using conventional surgical instruments and present the efforts currently underway at our institution to identify tumor invasion sites using 5-ALA-PDD.
