Aimee R Hayes1, Dasantha Jayamanne2, Edward Hsiao3, Geoffrey P Schembri4, Dale L Bailey5, Paul J Roach4, Mustafa Khasraw6, Allison Newey7, Helen R Wheeler6, Michael Back8. 1. Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia; Sydney Vital, Northern Translational Cancer Research Centre, St Leonards, NSW, Australia; Department of Medical Oncology, Royal North Shore Hospital, St Leonards, NSW, Australia. Electronic address: aimeehayes@hotmail.com. 2. Department of Radiation Oncology, Royal North Shore Hospital, St Leonards, NSW, Australia. 3. Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia. 4. Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW, Australia. 5. Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia; Sydney Vital, Northern Translational Cancer Research Centre, St Leonards, NSW, Australia; Faculty of Health Sciences, Cumberland Campus, The University of Sydney, Lidcombe, NSW, Australia. 6. Sydney Vital, Northern Translational Cancer Research Centre, St Leonards, NSW, Australia; Department of Medical Oncology, Royal North Shore Hospital, St Leonards, NSW, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW, Australia; Sydney Neuro-Oncology Group, North Shore Private Hospital, St Leonards, NSW, Australia. 7. Department of Radiology, Royal North Shore Hospital, St Leonards, NSW, Australia. 8. Sydney Vital, Northern Translational Cancer Research Centre, St Leonards, NSW, Australia; Department of Radiation Oncology, Royal North Shore Hospital, St Leonards, NSW, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW, Australia; Sydney Neuro-Oncology Group, North Shore Private Hospital, St Leonards, NSW, Australia.
Abstract
AIM: The authors sought to evaluate the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiation therapy planning for patients diagnosed with glioblastoma (GBM) and the presence of suspected nonenhancing tumors compared with standard magnetic resonance imaging (MRI). METHODS AND MATERIALS: Patients with GBM and contrast-enhanced MRI scans showing regions suspicious of nonenhancing tumor underwent postoperative FET-PET before commencing radiation therapy. Two clinical target volumes (CTVs) were created using pre- and postoperative MRI: MRI fluid-attenuated inversion recovery (FLAIR) sequences (CTVFLAIR) and MRI contrast sequences with an expansion on the surgical cavity (CTVSx). FET-PET was used to create biological tumor volumes (BTVs) by encompassing FET-avid regions, forming BTVFLAIR and BTVSx. Volumetric analyses were conducted between CTVs and respective BTVs using Wilcoxon signed-rank tests. The volume increase with addition of FET was analyzed with respect to BTVFLAIR and BTVSx. Presence of focal gadolinium contrast enhancement within previously nonenhancing tumor or within the FET-avid region was noted on MRI scans at 1 and 3 months after radiation therapy. RESULTS: Twenty-six patients were identified retrospectively from our database, of whom 24 had demonstrable FET uptake. The median CTVFLAIR, CTVSx, BTVFLAIR, and BTVSx were 57.1 mL (range, 1.1-217.4), 83.6 mL (range, 27.2-275.8), 62.8 mL (range, 1.1-307.3), and 94.7 mL (range, 27.2-285.5), respectively. When FET-PET was used, there was a mean increase in volume of 26.8% from CTVFLAIR to BTVFLAIR and 20.6% from CTVSx to BTVSx. A statistically significant difference was noted on Wilcoxon signed-rank test when assessing volumetric change between CTVFLAIR and BTVFLAIR (P < .0001) and CTVSx and BTVSx (P < .0001). Six of 24 patients (25%) with FET avidity before radiation therapy showed focal gadolinium enhancement within the radiation therapy portal. CONCLUSIONS: FET-PET may help improve delineation of GBM in cases with a suspected nonenhancing component. This may result in improved radiation therapy target delineation and reduce the risk of potential geographical miss. SUMMARY: We investigated the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiation therapy planning for patients diagnosed with glioblastoma (GBM) and a suspected nonenhancing tumor compared with standard magnetic resonance imaging. We performed volumetric analyses between clinical target volumes and respective biological target volumes using Wilcoxon signed-rank tests. FET-PET may help improve delineation of GBM in cases with a suspected nonenhancing component and reduce the risk of potential geographical miss.
AIM: The authors sought to evaluate the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiation therapy planning for patients diagnosed with glioblastoma (GBM) and the presence of suspected nonenhancing tumors compared with standard magnetic resonance imaging (MRI). METHODS AND MATERIALS: Patients with GBM and contrast-enhanced MRI scans showing regions suspicious of nonenhancing tumor underwent postoperative FET-PET before commencing radiation therapy. Two clinical target volumes (CTVs) were created using pre- and postoperative MRI: MRI fluid-attenuated inversion recovery (FLAIR) sequences (CTVFLAIR) and MRI contrast sequences with an expansion on the surgical cavity (CTVSx). FET-PET was used to create biological tumor volumes (BTVs) by encompassing FET-avid regions, forming BTVFLAIR and BTVSx. Volumetric analyses were conducted between CTVs and respective BTVs using Wilcoxon signed-rank tests. The volume increase with addition of FET was analyzed with respect to BTVFLAIR and BTVSx. Presence of focal gadolinium contrast enhancement within previously nonenhancing tumor or within the FET-avid region was noted on MRI scans at 1 and 3 months after radiation therapy. RESULTS: Twenty-six patients were identified retrospectively from our database, of whom 24 had demonstrable FET uptake. The median CTVFLAIR, CTVSx, BTVFLAIR, and BTVSx were 57.1 mL (range, 1.1-217.4), 83.6 mL (range, 27.2-275.8), 62.8 mL (range, 1.1-307.3), and 94.7 mL (range, 27.2-285.5), respectively. When FET-PET was used, there was a mean increase in volume of 26.8% from CTVFLAIR to BTVFLAIR and 20.6% from CTVSx to BTVSx. A statistically significant difference was noted on Wilcoxon signed-rank test when assessing volumetric change between CTVFLAIR and BTVFLAIR (P < .0001) and CTVSx and BTVSx (P < .0001). Six of 24 patients (25%) with FET avidity before radiation therapy showed focal gadolinium enhancement within the radiation therapy portal. CONCLUSIONS:FET-PET may help improve delineation of GBM in cases with a suspected nonenhancing component. This may result in improved radiation therapy target delineation and reduce the risk of potential geographical miss. SUMMARY: We investigated the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiation therapy planning for patients diagnosed with glioblastoma (GBM) and a suspected nonenhancing tumor compared with standard magnetic resonance imaging. We performed volumetric analyses between clinical target volumes and respective biological target volumes using Wilcoxon signed-rank tests. FET-PET may help improve delineation of GBM in cases with a suspected nonenhancing component and reduce the risk of potential geographical miss.
Authors: Norbert Galldiks; Maximilian Niyazi; Anca L Grosu; Martin Kocher; Karl-Josef Langen; Ian Law; Giuseppe Minniti; Michelle M Kim; Christina Tsien; Frederic Dhermain; Riccardo Soffietti; Minesh P Mehta; Michael Weller; Jörg-Christian Tonn Journal: Neuro Oncol Date: 2021-06-01 Impact factor: 12.300
Authors: Aditya A Mohan; William H Tomaszewski; Aden P Haskell-Mendoza; Kelly M Hotchkiss; Kirit Singh; Jessica L Reedy; Peter E Fecci; John H Sampson; Mustafa Khasraw Journal: Front Oncol Date: 2021-06-16 Impact factor: 6.244