gms | German Medical Science

72. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

06.06. - 09.06.2021

18F-FET PET imaging following immunotherapy with DC vaccination in glioblastoma patients

18F-FET PET Bildgebung im Verlauf einer Immuntherapie mit DC Vakzinierung bei Glioblastom-Patienten

Meeting Abstract

  • presenting/speaker Marion Rapp - Universitätsklinikum Düsseldorf, Department of Neurosurgery, Düsseldorf, Deutschland
  • Angeliki Datsi - Universitätsklinikum Düsseldorf, Institute for Transplantation Diagnostics and Cell Therapeutics, Düsseldorf, Deutschland
  • Jörg Felsberg - University Hospital Düsseldorf, Institute of Neuropathology, Düsseldorf, Deutschland
  • Norbert Galldiks - Research Centre Jülich, Institute of Neuroscience and Medicine, Jülich, Deutschland
  • Karl-Josef Langen - Research Centre Jülich, Institute of Neuroscience and Medicine, Jülich, Deutschland
  • Marcel A. Kamp - Universitätsklinikum Düsseldorf, Department of Neurosurgery, Düsseldorf, Deutschland
  • Rüdiger V. Sorg - Universitätsklinikum Düsseldorf, Institute for Transplantation Diagnostics and Cell Therapeutics, Düsseldorf, Deutschland
  • Michael Sabel - Universitätsklinikum Düsseldorf, Department of Neurosurgery, Düsseldorf, Deutschland

Deutsche Gesellschaft für Neurochirurgie. 72. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgie. sine loco [digital], 06.-09.06.2021. Düsseldorf: German Medical Science GMS Publishing House; 2021. DocV001

doi: 10.3205/21dgnc001, urn:nbn:de:0183-21dgnc0014

Published: June 4, 2021

© 2021 Rapp et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

Text

Objective: In the ongoing phase-II GlioVax trial, patients with newly diagnosed glioblastoma are treated with DC vaccination as add-on to standard temozolomide chemoradiation after fluorescence-guided surgery. Due to the multimodal therapy including vaccination immunotherapy, the specificity of contrast-enhanced MRI to differentiate between tumor recurrence and treatment-related changes is low. We examined the diagnostic value of amino acid PET using O-(2-[18F]-Fluoroethyl)-L-Tyrosine (18F-FET) PET for this clinically important differentiation.

Methods: Patients enrolled in the GlioVax trial and with progressive MRI findings according to the RANO criteria underwent additional 18F-FET PET imaging. Treatment-related changes on 18F-FET PET were considered if the mean tumor-to-brain ratio was ≤ 2.0. Subsequently, MRI and 18F-FET PET findings were correlated with the clinicoradiological follow-up or neuropathological findings.

Results: Seventeen patients (n=10 vaccinated patients; n=7 control group, with temozolomide chemoradiation alone) received 23 additional 18F-FET PET scans (n=14 scans in vaccinated patients; n=9 scans in patients with standard therapy). In vaccinated patients, the median time between radiotherapy completion and progressive MRI was 6 months (range, 1-18 months). In contrast, in the control group, the median time to MRI progression was 2 months (range, 1-7 months).

In 8 18F-FET PET scans (performed in 4 vaccinated patients, and 4 patients with standard therapy) PET and MRI were congruent and indicated tumor progression. Further treatment of these patients: Vaccinated patients: 2 were referred to best supportive care, in two patients a re-resection was performed (NP diagnosis: 1: therapy induced changes; 1: recurrent tumor). Control group: one patient was referred to best supportive care, in 3 patients a re-resection was performed and tumor recurrence was confirmed.

In contrast to the corresponding MRI, findings of 15 18F-FET PET scans (performed in 10 vaccinated patients, and in 5 patients with standard therapy) were consistent with treatment-related changes and the patients remained stable for at least 3 months.

Conclusion: Following multimodal therapy including DC vaccination, treatment-related changes occurred more often and later than in patients undergoing standard therapy. Additional 18F-FET PET imaging is helpful to distinguish tumor progression from treatment-induced changes related to the applied multimodal therapy including DC vaccination.