Recurrent glioblastoma versus late posttreatment changes: diagnostic accuracy of O-(2-[18F]fluoroethyl)-L-tyrosine positron emission tomography (18F-FET PET). Issue 12 (6th September 2019)

• Record Type: Journal Article
• Authors: Bashir, Asma; Mathilde Jacobsen, Sofie; Mølby Henriksen, Otto; Broholm, Helle; Urup, Thomas; Grunnet, Kirsten; Andrée Larsen, Vibeke; Møller, Søren; Skjøth-Rasmussen, Jane; Skovgaard Poulsen, Hans; Law, Ian
• Is Part Of: Neuro-oncology. Volume 21:Issue 12(2019)
• Page Start: 1595
• Page End: 1606
• Publication Date: 2019-09-06
• Subjects: glioblastoma -- 18F-FET PET -- tumor recurrence -- posttreatment changes; Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noz166
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: Background: Diagnostic accuracy in previous studies of O -(2-[ 18 F]-fluoroethyl)-L-tyrosine ( 18 F-FET) PET in patients with suspected recurrent glioma may be influenced by prolonged dynamic PET acquisitions, heterogeneous populations, different non–standard-of-care therapies, and PET scans performed at different time points post radiotherapy. We investigated the diagnostic accuracy of a 20-minute 18 F-FET PET scan in MRI-suspected recurrent glioblastoma 6 months after standard radiotherapy and its ability to prognosticate overall survival (OS). Methods: In total, 146 glioblastoma patients with 168 18 F-FET PET scans were reviewed retrospectively. Patients with MRI responses to bevacizumab or undergoing re-irradiation or immunotherapy after 18 F-FET PET were excluded. Maximum and mean tumor-to-background ratios (TBRmax, TBRmean ) and biological tumor volume (BTV) were recorded and verified by histopathology or clinical/radiological follow-up. Thresholds of 18 F-FET parameters were determined by receiver operating characteristic (ROC) analysis. Prognostic factors were investigated in Cox proportional hazards models. Results: Surgery was performed after 104 18 F-FET PET scans, while clinical/radiological surveillance was used following 64, identifying 152 glioblastoma recurrences and 16 posttreatment changes. ROC analysis yielded thresholds of 2.0 for TBRmax, 1.8 for TBRmean, and 0.55 cm 3 for BTV in differentiating recurrent glioblastoma from posttreatment changes with the best performance of TBRmax (sensitivity 99%, specificity 94%; P < 0.0001) followed by BTV (sensitivity 98%, specificity 94%; P < 0.0001). Using these thresholds, 166 18 F-FET PET scans were correctly classified. Increasing BTV was associated with shorter OS ( P < 0.0001). Conclusion: A 20-minute 18 F-FET PET scan is a powerful tool to distinguish posttreatment changes from recurrent glioblastoma 6-month postradiotherapy, and predicts OS.