Artikel
Correlation of 5-ALA induced fluorescence with contrast enhancement on MRI, pre-operative FET-PET and tumor molecular factors in grade II and III astrocytomas
Suche in Medline nach
Autoren
Veröffentlicht: | 2. Juni 2015 |
---|
Gliederung
Text
Objective: Only about 20 % of LGG but most WHO III° fluoresce after 5-ALA-application. On the other hand approximately, 30% of gliomas without enhancement on the MRI are classified as WHO III°. The aim of this study was to identify ex ante factors (i. e. age, MRI enhancement, FET-PET) for predicting intraoperative fluorcescence in grade II°/III° gliomas and to determine whether fluorescence, if observed, would allow a prediction of pathohistology (II°/III°) or molecular tumor charactaristics.
Method: We analyzed all non-GBM gliomas operated on at our institution between 01/2012 and 12/2013 that had received 5-ALA for enhancement on MRI, or FET PET or positivity. Further, IDH1 mutation and MGMT promoter methylation were examined by direct sequencing and methylation-specific PCR, respectively. 1p19q co-deletion was detected by fluorescence in situ hybridization. Statistical analysis included multivariate and recursive partitioning analysis (RPA).
Results: Of 196 gliomas 101 were grade II and 95 grade III astroycatomas (29 anaplastic oligodendrogliomas or oligoastrocytoma), 66 anaplastic astrocytomas). FET-PET was performed in 143 patients and 159 patients were given 5-ALA.
From the ex ante perspective contrast-enhancement, tumor volume and a FET-PET SUV > 1,85 significantly predicted intra-operative fluorescence on RPA. Fluorescence corrlelated significantly with the WHO grade (P=0,000) and the. MIB-index (P=0,000) but not with MGMT promoter methylation (P=0.481), IDH1 mutation (P<0.101) and. 1p19q deletion (P=0.135).
Conclusions: We identified a number of ex ante factors for predicting the usefulness of 5-ALA in non-GBM glioma patients, such as age, tumor volume and FET-PET (SUV>1,85), also in tumors without contrast-enhancement. Fluorescence in astrocytoma tissue is significantly correlated to an increased MIB-Index and more frequently observed in WHO III° gliomas but not to commonly assessed molecular markers. Whether fluorescing grade II gliomas represent a subtype with a worse prognosis remains to be determined.