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.
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Authors | Karen Gauvain, Maria Rosana Ponisio, Amy Barone, Michael Grimaldi, Ephraim Parent, Hayden Leeds, Manu Goyal, Joshua Rubin, Jonathan McConathy |
Journal | Neuro-oncology practice
(Neurooncol Pract)
Vol. 5
Issue 1
Pg. 28-36
(Mar 2018)
ISSN: 2054-2577 [Print] England |
PMID | 29692922
(Publication Type: Journal Article)
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