title: [18F]fluoroethyltyrosine-positron emission tomography-based therapy monitoring after stereotactic iodine-125 brachytherapy in patients with recurrent high-grade glioma.
abstract: Therapy monitoring of glioma after stereotactic iodine-125 brachytherapy (SBT) remains challenging because posttherapeutic changes in magnetic resonance imaging can mimic tumor progression. We evaluated the prognostic value of serial [18F]fluoroethyltyrosine (FET)-positron emission tomographic (PET) scans for therapy monitoring of high-grade glioma (HGG) after SBT. Thirty-three patients with recurrent HGG were included. Serial FET-PET scans were performed prior to therapeutic intervention and at 3-month intervals during the first year after SBT. FET-PET evaluation was performed by both conventional data analysis and kinetic analysis. Prognostic factors were obtained from proportional hazard models. Median local progression-free survival (LPFS) was 11.1 months. Maximal standardized background uptake value (SUVmax/BG) and biologic tumor volume (BTV) differentiated accurately between therapeutic effects and local tumor progression at the 6-month and subsequent examinations. Increasing uptake kinetics at baseline (p < .05) and during follow-up (p < .01) were stringently associated with a longer LPFS. Early increase in FET uptake after SBT is not unequivocally associated with tumor progression; it might be induced by reactive changes and could easily lead to a misclassification of the tumor status (pseudoprogression). Six months after SBT (or later), however, increased SUVmax/BG and BTV values are associated with a worse prognosis. Multivariate analysis stresses the prognostic importance of dynamic studies.
authors.affiliation: Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany.
authors.forename: Nathalie L
authors.initials: NL
authors.lastname: Jansen
authors.forename: Bogdana
authors.initials: B
authors.lastname: Suchorska
authors.forename: Silke B
authors.initials: SB
authors.lastname: Schwarz
authors.forename: Sabina
authors.initials: S
authors.lastname: Eigenbrod
authors.forename: Juergen
authors.initials: J
authors.lastname: Lutz
authors.forename: Vera
authors.initials: V
authors.lastname: Graute
authors.forename: Peter
authors.initials: P
authors.lastname: Bartenstein
authors.forename: Claus
authors.initials: C
authors.lastname: Belka
authors.forename: Friedrich W
authors.initials: FW
authors.lastname: Kreth
authors.forename: Christian
authors.initials: C
authors.lastname: la Fougère
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D018572:Disease-Free Survival; D005910:Glioma / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy*; D006801:Humans; D007455:Iodine / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D014443:Tyrosine / Q000031:analogs & derivatives*
chemical_list: C117289:O-(2-fluoroethyl)tyrosine; D014443:Tyrosine; D007455:Iodine