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Tippayamontri T, Guérin B, Ouellet R, Sarrhini O, Rousseau J, Lecomte R, Paquette B, Sanche L. Intratumoral 18F-FLT infusion in metabolic targeted radiotherapy. EJNMMI Res 2019; 9:33. [PMID: 30972596 PMCID: PMC6458198 DOI: 10.1186/s13550-019-0496-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 03/11/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The goal of targeted radiotherapy (TRT) is to administer radionuclides to tumor cells, while limiting radiation exposure to normal tissues. 3'-Deoxy-3'-[18F]-fluorothymidine (18F-FLT) is able to target tumor cells and emits a positron with energy appropriate for local (~ 1 mm range) radiotherapy. In the present work, we investigated the potential of TRT with a local administration of 18F-FLT alone or in combination with 5-fluorouracil (5FU), which acts as a chemotherapeutic agent and radiosensitizer. Treatment efficiency of 18F-FLT combined or not with 5FU was evaluated by intratumoral (i.t.) infusion into subcutaneous HCT116 colorectal tumors implanted in nu/nu mice. The tumor uptake and kinetics of 18F-FLT were determined and compared to 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) by dynamic positron emission tomography (PET) imaging following i.t. injection. The therapeutic responses of 18F-FLT alone and with 5FU were evaluated and compared with 18F-FDG and external beam radiotherapy (EBRT). The level of prostaglandin E2 (PGE2) biosynthesis was measured by liquid chromatography/tandem mass spectrometry (LC/MS/MS) in order to determine the level of inflammation to healthy tissues surrounding the tumor, after i.t. injection of 18F-FLT, and compared to EBRT. RESULTS We found that i.t. administration of 18F-FLT offers (1) the highest tumor-to-muscle uptake ratio not only in the injected tumor, but also in distant tumors, suggesting potential for concurrent metastases treatment and (2) a sixfold gain in radiotherapeutic efficacy in the primary tumor relative to EBRT, which can be further enhanced with concurrent i.t. administration of the radiosensitizer 5FU. While EBRT stimulated PGE2 production in peritumoral tissues, no significant increase of PGE2 was measured in this area following i.t. administration of 18F-FLT. CONCLUSION Considering the biochemical stability of 18F-FLT and the physical properties of localized 18F, this study shows that TRT via intratumoral infusion of 18F-FLT and 5FU could provide a new effective treatment option for solid tumors. Using this approach in a colorectal tumor model, the tumor and its metastases could be efficiently irradiated locally with much lower doses absorbed by healthy tissues than with i.t. administration of 18F-FDG or conventional EBRT.
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Affiliation(s)
- Thititip Tippayamontri
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada. .,Center of Radiotherapy Research, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, QC, Canada. .,Department of Radiological Technology and Medical Physics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand.
| | - Brigitte Guérin
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Sherbrooke Molecular Imaging Center, CRCHUS, Sherbrooke, QC, Canada
| | - René Ouellet
- Sherbrooke Molecular Imaging Center, CRCHUS, Sherbrooke, QC, Canada
| | - Otman Sarrhini
- Sherbrooke Molecular Imaging Center, CRCHUS, Sherbrooke, QC, Canada
| | - Jacques Rousseau
- Sherbrooke Molecular Imaging Center, CRCHUS, Sherbrooke, QC, Canada
| | - Roger Lecomte
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Sherbrooke Molecular Imaging Center, CRCHUS, Sherbrooke, QC, Canada
| | - Benoit Paquette
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Center of Radiotherapy Research, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, QC, Canada
| | - Léon Sanche
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Center of Radiotherapy Research, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, QC, Canada
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