Evaluation of the Impact of Magnetic Resonance Imaging (MRI) on Gross Tumor Volume (GTV) Definition for Radiation Treatment Planning (RTP) of Inoperable High Grade Gliomas (HGGs)

Selcuk Demiral,Bora Uysal,Hakan Gamsiz,Ferrat Dincoglan,Omer Sager,Murat Beyzadeoglu,Fatih Ozcan,Onurhan Colak,Bahar Dirican

doi:10.1155/2019/4282754

Selcuk Demiral, Bora Uysal + Show 7 more

Open Access

https://doi.org/10.1155/2019/4282754

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Abstract

Aim and Background. Inoperable high-grade gliomas (HGGs) comprise a specific group of brain tumors portending a very poor prognosis. In the absence of surgical management, radiation therapy (RT) offers the primary local treatment modality for inoperable HGGs. Optimal target definition for radiation treatment planning (RTP) of HGGs is a difficult task given the diffusely infiltrative nature of the disease. In this context, detailed multimodality imaging information may add to the accuracy of target definition in HGGs. We evaluated the impact of Magnetic Resonance Imaging (MRI) on Gross Tumor Volume (GTV) definition for RTP of inoperable HGGs in this study. Materials and Methods. Twenty-five inoperable patients with a clinical diagnosis of HGG were included in the study. GTV definition was based on Computed Tomography- (CT-) simulation images only or both CT-simulation and MR images, and a comparative assessment was performed to investigate the incorporation of MRI into RTP of HGGs. Results. Median volume of GTV acquired by using CT-simulation images only and by use of CT and MR images was 65.3 (39.6-94.3) cc and 76.1 (46.8-108.9) cc, respectively. Incorporation of MRI into GTV definition has resulted in a median increase of 12.61% (6%-19%) in the volume of GTV defined by using the CT-simulation images only, which was statistically significant (p < 0.05). Conclusion. Incorporation of MRI into RTP of inoperable HGGs may improve GTV definition and may have implications for dose escalation/intensification strategies despite the need for further supporting evidence.

Highlights

High-grade gliomas (HGGs) refer to World Health Organization (WHO) grades III and IV gliomas including glioblastoma (GB), anaplastic astrocytoma, and anaplastic oligodendroglioma [1]
Gross Tumor Volume (GTV) definition was based on Computed Tomography- (CT-)simulation images only or both CT-simulation and MR images, and a comparative assessment was performed to investigate the incorporation of Magnetic Resonance Imaging (MRI) into radiation treatment planning (RTP) of HGGs
A total of 25 patients referred for definitive radiation therapy (RT) at our institution for inoperable HGG were assessed for GTV definition based on CT-simulation images only or both CT-simulation and MR images

Summary

Introduction

High-grade gliomas (HGGs) refer to World Health Organization (WHO) grades III and IV gliomas including glioblastoma (GB), anaplastic astrocytoma, and anaplastic oligodendroglioma [1]. Maximal surgical removal of the tumor followed by chemoradiotherapy has been the standard of care for newly diagnosed GB patients after the landmark trial of European Organisation for Research and Treatment of Cancer (EORTC)/National Cancer Institute of Canada Clinical Trials Group (NCICCTG) in 2005 and has been widely practiced worldwide [11]. This practice-changing study has demonstrated prolonged overall survival with the addition of temozolomide (TMZ) to conventionally fractionated radiation therapy (RT) and paved the way for future trials for further achievements [11]. There is still room for improvement, and there is extensive research on management of GB [12]

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