18f-Fluorocholine PET/CT as a Prognostic Tool in High-grade Gliomas

Introduction: High-grade gliomas are characterized by a diffuse infiltrating growth. This makes complete tumor removal very challenging. 5-aminolevulinic acid (5-ALA) has shown to increase extent of resection. Postoperative contrast-enhanced MRI is used to determine level of resection and to assess recurrence. The aim of this study is to compare postoperative 18F-Fluorocholine PET/CT with 5-ALA and postoperative MRI in diagnosing complete resection and its possible use as a prognostic tool.

Methods: We conducted a prospective study including patients who underwent surgical resection of high-grade gliomas between July 2016 and August 2020, who had a postoperative contrast-enhanced MRI and 18F-Fluorocholine PET/CT. Results of these exams, as well as level of resection using 5-ALA were assessed. 5-ALA was classified as positive (no complete fluorescence removal) or negative. Postoperative MRI was classified as total or subtotal resection. 18F-Fluorocholine PET/CT was classified according to the FUMeGA 5-points score system. Concordance of 5-ALA, postoperative MRI and postoperative 18F-Fluorocholine PET/CT was analyzed (Cohen K). The role in predicting progression free survival and overall survival was assessed by Kaplan-Meier method and Cox regression analysis.

Results: A total of 52 studies belonging to 48 patients were obtained. Concordance between 5-ALA, postoperative MRI and postoperative 18F-Fluorocholine PET/CT was poor. Only 18F-Fluorocholine PET/CT showed a significant association with progression free survival (p=0.012) and no association with overall survival was found. In multivariate analysis, no significance was found.

Conclusion : Previous studies have shown 18F-Fluorocholine PET/CT to be a good alternative to postoperative MRI and its utility as a prognostic tool. Our study seems to agree with this but fails to show statistical significance in multivariate analysis. Further research is necessary in order to prove our results.