Voxel-Wise Analysis of Fluoroethyltyrosine PET and MRI in the Assessment of Recurrent Glioblastoma During Antiangiogenic Therapy.
FET; MRI; PET; bevacizumab; fluoroethyl tyrosine; glioblastoma
OBJECTIVE: In MRI of patients with recurrent glioblastoma, bevacizumab-induced normalization of tumor vascularity can be difficult to differentiate from antitumor effects. The aim of this study was to assess the utility of
SUBJECTS AND METHODS: MRI and FET PET were performed before and after administration of two doses of bevacizumab to 11 patients with recurrent glioblastoma. The ratio between normalized FET uptake at follow-up and baseline of the entire (volume of T2 FLAIR abnormality) and enhancing tumor were assessed for prediction of progression-free survival (PFS) and overall survival (OS). Voxel-wise Spearman correlation between normalized FET uptake and contrast-enhanced T1 signal intensity was assessed and tested as a predictor of PFS and OS.
RESULTS: Mean Spearman correlation between FET uptake and contrast-enhanced T1 signal intensity before therapy was 0.65 and after therapy was 0.61 (p = 0.256). The median PFS after initiation of bevacizumab therapy was 111 days, and the OS was 223 days. A post-treatment to pretreatment PET uptake ratio (mean and 90th percentile) greater than 0.7 for both entire and enhancing tumor was associated with lower PFS and OS (p < 0.001-0.049). The increase in correlation between PET uptake and contrast-enhanced T1 intensity after treatment was associated with lower PFS (p < 0.001) and OS (p = 0.049).
CONCLUSION: There is only a moderate correlation between FET PET uptake and contrast-enhanced T1 signal intensity. High posttreatment-to-pretreatment FET PET uptake ratio and increase in correlation between PET uptake and contrast-enhanced T1 signal intensity after bevacizumab treatment are associated with poor PFS and OS.
Neurosciences (Brain & Spine)
George, Elizabeth; Kijewski, Marie F; Dubey, Shipra; Belanger, Anthony P; Reardon, David A; Wen, Patrick Y; Kesari, Santosh; Horky, Laura; Park, Mi-Ae; and Huang, Raymond Y, "Voxel-Wise Analysis of Fluoroethyltyrosine PET and MRI in the Assessment of Recurrent Glioblastoma During Antiangiogenic Therapy." (2018). Articles, Abstracts, and Reports. 789.