IDH mutation is paradoxically associated with higher 18F-FDOPA PET uptake in diffuse grade II and grade III gliomas

Abstract

This study showed paradoxically higher F-FDOPA uptake in diffuse grade II and III gliomas with IDH mutation. Despite evident interest in the management of gliomas, and especially in relation to posttherapy evaluation, our findings raise the question of the prognostic value ofF-FDOPA uptake on PET uptake in this group of patients. This may be related to differences in amino acid integration, metabolism, or cell differentiation.

Is IDH mutation status associated with 18F-FDopa PET uptake?

“…The authors state that 6-[18F]fuoro-l-DOPA (18F-FDopa) PET uptake is not signifcantly diferent between IDH-mutant and IDH-wildtype gliomas in a population composed of diffuse gliomas as well as glioblastomas. At frst glance, these results appear to be inconsistent with regard to the article published earlier by our team [2]. Indeed, we concluded that the IDH mutation, which is a factor of good prognosis, was paradoxically associated with a higher uptake of 18F-FDopa PET in a series of difuse gliomas.…”

“…When considering our whole population including both difuse gliomas and glioblastomas, we found that static parameters failed to diferentiate IDH-mutant from IDHwildtype gliomas (p=0.69 for the TBRmean and p=0.53 for MTV). However, when focusing the analysis on difuse gliomas only, static parameters showed to be paradoxically associated with IDH mutation status, confrming the results of our previous article [2]. Specifcally, the MTV was signifcantly higher in IDH-mutant difuse gliomas (p=0.002) while a substantial trend toward a higher TBRmean in these IDH-mutant difuse gliomas was also observed (p=0.10).…”

“…Firstly, Cicone et al did not use a fxed threshold to segment their tumor volume, leading to MTVs which were hardly comparable. Secondly, in the publication by Cicone et al, most patients underwent their stereotaxic biopsy prior to having undergone their 18F-FDopa PET, which can afect tumor uptake by removing a portion of the tumor (94% in [1] vs. 2% in [2] and 12% in [4]).…”

Use of static and dynamic 18F-FDopa PET parameters for detecting patients with glioma recurrence or progression

“…The main limitations inherent to this study are that results were obtained retrospectively, in a single center. In addition, our sample size was too limited for providing separate analyses according to the different molecular features of the gliomas involved in the present study, whereas 18 F-FDopa uptake is known varying according to these features [37]. These findings hence need to be confirmed in further multicenter prospective studies planned in larger populations.…”

PET and MRI in gliomas: progress and perspectives

“…There has been huge progress with molecular PET and multimodal MR imaging methods, but many brain tumour PET papers published so far fail to compare imaging results with other molecular markers such as MGMT, IDH1, and EGFR mutations and 1p/19q co-deletion [16], which are regarded as standard tools and may actually provide similar, complementary, or possibly even conflicting diagnostic and prognostic information [17]. Thus, future imaging studies need to compare results with these markers for the classification and management of brain tumours.…”