18F-FDOPA PET/MRI for monitoring early response to bevacizumab in children with recurrent brain tumors

Karen Gauvain, Maria Rosana Ponisio, Amy Barone, Michael Grimaldi, Ephraim Parent, Hayden Leeds, Manu Goyal, Joshua Rubin, Jonathan McConathy

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Background: Noninvasively predicting early response to therapy in recurrent pediatric brain tumors provides a challenge. 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (18F-FDOPA) PET/MRI has not been previously studied as a tool to evaluate early response to antiangiogenic therapy in children. The purpose of this study was to evaluate the safety and feasibility of using 18F-FDOPA PET/MRI to assess response to bevacizumab in children with relapsed brain tumors. Materials and Methods: Six patients with recurrent gliomas (5 low-grade, 1 high-grade) planned to undergo treatment with bevacizumab were enrolled. 18F-FDOPA PET/MRI scans were obtained prior to and 4 weeks following the start of treatment, and these were compared with the clinical response determined at the 3-month MRI. The primary PET measure was metabolic tumor volume (MTV) at 10 to 15 min after 18F-FDOPA injection. For each tumor, the MTV was determined by manually defining initial tumor volumes of interest (VOI) and then applying a 1.5-fold threshold relative to the mean standardized uptake value (SUV) of a VOI in the frontal lobe contralateral to the tumor. Results: 18F-FDOPA PET/MRI was well tolerated by all patients. All tumors were well visualized with 18F-FDOPA on the initial study, with peak tumor uptake occurring approximately 10 min after injection. Maximum and mean SUVs as well as tumor-to-brain ratios were not predictors of response at 3 months. Changes in MTVs after therapy ranged from 23% to 98% (n = 5). There is a trend towards the percent MTV change seen on the 4-week scan correlating with progression-free survival. Conclusion: 18F-FDOPA PET/MRI was well tolerated in pediatric patients and merits further investigation as an early predictor of response to therapy.

Original languageEnglish
Pages (from-to)28-36
Number of pages9
JournalNeuro-Oncology Practice
Volume5
Issue number1
DOIs
StatePublished - Mar 2 2018

Keywords

  • Bevacizumab
  • FDOPA PET
  • Monitoring response
  • Pediatric brain tumors
  • Recurrent brain tumors

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