Comparison of Three-Dimensional Conformal Radiation Therapy, Intensity-Modulated Radiation Therapy, and Volumetric- Modulated Arc Therapy In Glioblastoma Multiforme Radiation Therapy With EORTC Target Delineation
Kamuran İBİŞ1,Uğur AKBAŞ2,Canan KÖKSAL2,Musa ALTUN1
1Department of Radiation Oncology, Istanbul University, Institute of Oncology, Istanbul-Turkey
2Department of Institute of Oncology, Istanbul University, Division of Medical Physics, Istanbul-Turkey
DOI : 10.5505/tjo.2018.1769 OBJECTIVE
In this study, three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated RT (IMRT), and volumetric-modulated arc therapy (VMAT) techniques were compared in patients with glioblastoma multiforme (GBM) receiving RT. Comparisons were made in terms of sparing the organs at risk (OAR), by using European Organisation for Research and Treatment of Cancer-Advisory Committee on Radiation Oncology Practise (EORTC-ACROP) guideline.

RT in 10 patients was replanned. Treatment volume was created according to the EORTC-ACROP, and 60 Gy/30 fraction dose was prescribed for planning target volume (PTV). PTV-less brain volume (BPTV) Dmean, OARs doses; V5Gy and V50Gy of B-PTV volumes; conformality, and homogeneity indices were analyzed.

B-PTV was spared better in IMRT. The optic chiasm, contralateral optic nerve, ipsilateral/contralateral cochlea were significantly spared in IMRT and VMAT. The best sparing for brainstem, pituitary gland, ipsilateral eye, ipsilateral lacrimal gland was obtained with VMAT. B-PTV volume received at least 5 Gy was similar in three plans, but lower with 50 Gy in IMRT and VMAT (p<0.001). Although homogenous dose distribution was obtained with similar homogeneity index in all three planning techniques, conformity index was the best in VMAT (p<0.001).

VMAT provides improved conformity index and good homogeneity in GBM RT using the EORTCACROP target and dose definition. The best sparing for OAR was obtained with VMAT. Keywords : Glioblastoma multiforme; intensity-modulated radiotherapy; three-dimensional conformal radiotherapy; volumetric-modulated arc therapy