Evolution of the gross tumour volume extent during radiotherapy for glioblastomas. (July 2021)

• Record Type: Journal Article
• Authors: Bernchou, Uffe; Arnold, Trine Skak Tranemose; Axelsen, Brit; Klüver-Kristensen, Mette; Mahmood, Faisal; Harbo, Frederik Severin Gråe; Asmussen, Jon Thor; Hansen, Olfred; Bertelsen, Anders Smedegaard; Hansen, Steinbjørn; Brink, Carsten; Dahlrot, Rikke Hedegaard
• Is Part Of: Radiotherapy and oncology. Volume 160(2021)
• Page Start: 40
• Page End: 46
• Publication Date: 2021-07
• Subjects: CT Computed tomography -- CTV Clinical target volume -- Dmax Maximum distance -- EANO European Association for Neuro-Oncology -- ECOG Eastern Cooperative Oncology Group -- FLAIR Fluid-attenuated inversion recovery -- GBM Glioblastoma multiforme -- GTV Gross tumour volume -- GTV10 GTV delineated on MR10 -- GTV20 GTV delineated on MR20 -- GTV30 GTV delineated on MR30 -- GTVFU GTV delineated on MRFU -- GTVP GTV delineated on MRP -- MRI Magnetic resonance imaging -- MR10 MRI acquired at fraction 10 -- MR20 MRI acquired at fraction 20 -- MR30 MRI acquired at fraction 30 -- MRFU MRI acquired at follow-up -- MRP MRI acquired for treatment planning -- R-GTV The relative GTV volume -- RT Radiotherapy -- RTOG Radiation Therapy Oncology Group -- TMZ Temozolomide; Glioblastoma -- Magnetic resonance imaging -- Adaptive radiotherapy -- Prospective study; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2021.04.001
• Languages: English
• ISSNs: 0167-8140

Abstract

Graphical abstract: Highlights: Changes in glioblastoma tumour extent often occur early during treatment course. The evolution of the tumour volume varies among patients. Early changes in tumour volume and extent correlates with changes at follow-up. Plan adaptation was not needed to cover the tumour with dose during radiotherapy. Abstract: Background and purpose: Tumour growth during radiotherapy may lead to geographical misses of the target volume. This study investigates the evolution of the tumour extent and evaluates the need for plan adaptation to ensure dose coverage of the target in glioblastoma patients. Materials and methods: The prospective study included 29 patients referred for 59.4 Gy in 33 fractions. Magnetic resonance imaging (MRI) was performed at the time of treatment planning, at fraction 10, 20, 30, and three weeks after the end of radiotherapy. The gross tumour volume (GTV) was defined as the T1w contrast-enhanced region plus the surgical cavity on each MRI set. The relative GTV volume and the maximum distance ( D max ) of the extent of the actual GTV outside the original GTV were measured. Based on the location of the actual GTV during radiotherapy and the original planned dose, a prospective clinical decision was made whether to adapt the treatment. Results: Dose coverage of the GTV during radiotherapy was not compromised, and none of the radiotherapy plans was adapted. The median D max (range) was 5.7 (2.0–18.9) mm, 8.0 (2.0–27.4) mm, 8.0 (1.9–27.3) mm, and 8.9 (1.9–34.4) mm at fraction 10, 20, 30, and follow-up. The relative GTV volume and D max observed at fraction 10 were correlated with the values observed at follow-up ( R = 0.74, p < 0.001 and R = 0.79, p < 0.001, respectively). Conclusion: Large variations in the GTV extent were observed, and changes often occurred early in the treatment. Plan adaptation for geographical misses was not performed in our cohort due to sufficient CTV margins.