Prognostic value of18F-FET PET imaging in re-irradiation of high-grade glioma: Results of a phase I clinical trial.
Positron emission tomography (PET) provides quantitative metabolic information and potential biomarkers of treatment outcome. We aimed to determine the prognostic value of early18F-fluoroethyl-tyrosine (18F-FET) PET scans acquired during re-irradiation for recurrent high-grade glioma (HGG).



A phase I clinical trial of re-irradiation of HGG was carried out. MRI and18F-FET PET were used for target delineation and follow-up. Images were acquired at baseline, during radiotherapy and 4weeks post-treatment and compared by measuring the metabolically active biological tumor volume (BTV) and maximal activity (Tmax/B). Correlations with outcomes were assessed by multivariate Cox regression analysis.



Thirty-one patients were included and all patients have died. The median overall survival was 7.0 mos. Both baseline BTV and baseline MRI volume (necrotic/cystic cavities subtracted) were prognostic for overall survival (OS) in multivariate analysis (HR=1.3 p<0.01 and HR=1.3 p<0.01, respectively). Early changes in BTV and Tmax/B were observed but they carried no independent prognostic information.



Baseline biological tumor volume (BTV) defined by18F-FET PET was prognostic for OS in multivariate analysis, as was MRI volume (necrotic/cystic cavities subtracted). Tumor volume may aid in identifying patients whose life expectancy is too short to warrant re-irradiation.
Department of Oncology, Rigshospitalet, University of Copenhagen, Denmark. Electronic address: dr.smoller@gmail.com.
Soren
S
Moller
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen, Denmark.
Ian
I
Law
Department of Oncology, Rigshospitalet, University of Copenhagen, Denmark.
Per
P
Munck Af Rosenschold
Department of Oncology, Rigshospitalet, University of Copenhagen, Denmark; Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen, Denmark.
Junia
J
Costa
Department of Oncology, Rigshospitalet, University of Copenhagen, Denmark; Department of Radiation Biology, Rigshospitalet, University of Copenhagen, Denmark.
Hans Skovgaard
HS
Poulsen
Department of Oncology, Rigshospitalet, University of Copenhagen, Denmark.
Svend Aage
SA
Engelholm
Department of Oncology, Rigshospitalet, University of Copenhagen, Denmark; Department of Oncology, Skåne University Hospital, Lund, Sweden.
Silke
S
Engelholm
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D000069475:Re-Irradiation / Q000379:methods; D016896:Treatment Outcome; D047368:Tumor Burden; D014443:Tyrosine / Q000031:analogs & derivatives*
D019275:Radiopharmaceuticals; C545932:(18F)fluoroethyltyrosine; D014443:Tyrosine
High-grade glioma; MRI; Metabolic imaging; Positron emission tomography; Prognostic markers; Re-irradiation