Abstract
Abstract BACKGROUND Pediatric High-Grade Glioma/ diffuse midline glioma (pHGG/DMG) growth during a six-week course of radiotherapy may precipitate geographical miss of target volumes and early disease progression. In a patient cohort, we retrospectively evaluated the evolution of tumor volumes during radiotherapy, the clinical need for plan adaptation, and potential correlation with local disease progression. METHODS Twenty-four pHGG/DMG patients (12M/12F, ages 4-20 years) with gross tumor volume (GTV) after debulking (n=7) or biopsy (n=17) received 30 fractions of Volumetric Modulated Arc Therapy within an adaptive radiotherapy-protocol. The GTV was defined by combined T1+FLAIR MRI sequence abnormalities. A 1-cm margin was applied for Clinical Target Volume (CTV). MRI-based target volume re-evaluation was performed at fraction 10 and 20, defining GTV increase >1mL as growth. The clinical need for plan adaptation was based on tumor volume changes. GTV increase and need for plan adaptation were evaluated against local progression-free survival (LPFS). RESULTS Median time between baseline MRI and radiotherapy start was 10 days (range 3-29). From baseline, GTV growth was observed in 7/24 patients at fraction 10, and in an additional 7/24 patients at fraction 20 (cumulative 14/24), corresponding to a mean volume increase of 21%/3.7mL (range [-7%/-2.7mL] to [+185%/24.4mL]) and 40%/8.7mL (range [-18%/-8.1mL] to [+329%/115.1mL]) after 10 and 20 fractions, respectively. At fraction 10 and 20, respectively 6 and 6 plans needed adaptation in a total of 11 patients. Baseline tumor volumes between patients with/without plan adaptation were equivalent. Median LPFS was 8.3 months (95%CI 8.0-12.7). No significant difference in LPFS was observed between patients with versus without GTV increase or plan adaptation. CONCLUSIONS Between MRI at baseline and at fractions 10 and 20, this adaptive radiotherapy protocol using 1-cm CTV margins demonstrated pHGG/DMG tumor volume increase with a clinical need for plan adaptations in 11/24 patients.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.