%0 Journal Article %A Ceccon, G. %A Lohmann, Philipp %A Werner, Jan-Michael %A Caroline, Tscherpel %A Dunkl, Veronika %A Stoffels, Gabriele %A Rosen, Jurij %A Rapp, Marion %A Herrlinger, Ulrich %A Schäfer, Niklas %A Shah, N. J. %A Fink, Gereon Rudolf %A Langen, Karl-Josef %A Galldiks, Norbert %T Early treatment response assessment using $^{18}$F-FET PET compared to contrast-enhanced MRI in glioma patients after adjuvant temozolomide chemotherapy %J Journal of nuclear medicine %V 62 %N 7 %@ 0022-3123 %C New York, NY %I Soc. %M FZJ-2020-04140 %P 918-925 %D 2021 %X The goal of this study was to compare the value of contrast-enhanced MRI and O-(2-[18F]fluoroethyl)-l-tyrosine (18F-FET) PET for response assessment in glioma patients after adjuvant temozolomide chemotherapy (TMZ). Methods: After biopsy or resection and completion of radiotherapy with concomitant TMZ, 41 newly diagnosed and histomolecularly characterized glioma patients (glioblastoma, 90%; age range, 20–79 y) were subsequently treated with adjuvant TMZ. MR and 18F-FET PET imaging were performed at baseline and after the second cycle of adjuvant TMZ. We obtained 18F-FET metabolic tumor volumes (MTVs) as well as mean and maximum tumor-to-brain ratios (TBRmean and TBRmax, respectively). Threshold values of 18F-FET PET parameters to predict outcome were established by receiver-operating-characteristic analyses using a median progression-free survival (PFS) of ≥ 9 mo and overall survival (OS) of ≥ 15 mo as reference. MRI response assessment was based on the Response Assessment in Neuro-Oncology (RANO) working group criteria. The predictive value of changes of 18F-FET PET and MRI parameters on survival was evaluated subsequently using univariate and multivariate survival estimates. Results: After 2 cycles of adjuvant TMZ chemotherapy, a treatment-induced reduction of MTV and TBRmax predicted a significantly longer PFS and OS (both P ≤ 0.03; univariate survival analyses) whereas RANO criteria were not significant (P > 0.05). Multivariate survival analysis revealed that TBRmax changes predicted a prolonged PFS (P = 0.012) and changes of MTV a prolonged OS (P = 0.005) independent of O6-methylguanine-DNA-methyltransferase promoter methylation and other strong prognostic factors. Conclusion: Changes of 18F-FET PET parameters appear to be helpful for identifying responders to adjuvant TMZ early after treatment initiation. %F PUB:(DE-HGF)16 %9 Journal Article %$ pmid:33158907 %U <Go to ISI:>//WOS:000709477900011 %R 10.2967/jnumed.120.254243 %U https://juser.fz-juelich.de/record/885860