Radiation Necrosis, Pseudoprogression, Pseudoresponse, and Tumor Recurrence: Imaging Challenges for the Evaluation of Treated Gliomas.

Anastasia Zikou,Chrissa Sioka,Spyridon Voulgaris,George A Alexiou,Andreas Fotopoulos,Maria I Argyropoulou

doi:10.1155/2018/6828396

Anastasia Zikou, Chrissa Sioka + Show 4 more

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https://doi.org/10.1155/2018/6828396

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Abstract

Glioblastoma (GBM) is the most common primary malignant type of brain neoplasm in adults and carries a dismal prognosis. The current standard of care for GBM is surgical excision followed by radiation therapy (RT) with concurrent and adjuvant temozolomide-based chemotherapy (TMZ) by six additional cycles. In addition, antiangiogenic therapy with an antivascular endothelial growth factor (VEGF) agent has been used for recurrent glioblastoma. Over the last years, new posttreatment entities such as pseudoprogression and pseudoresponse have been recognized, apart from radiation necrosis. This review article focuses on the role of different imaging techniques such as conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), dynamic contrast enhancement (DCE-MRI) and dynamic susceptibility contrast (DSE-MRI) perfusion, magnetic resonance spectroscopy (MRS), and PET/SPECT in differentiation of such treatment-related changes from tumor recurrence.

Highlights

Glioblastoma (GBM) is the most malignant primary brain tumor in adults with dismal prognosis [1]
We reviewed the current evidence on the ability of imaging techniques such as magnetic resonance imaging (MRI), SPECT, and PET for the detection of glioma recurrence/progression
Brades et al proposed that tumors with methylation of the MGMT promoter, due to greater effect of the combination of temozolomide and radiotherapy to residual tumor, produce a temporary worsening of imaging characteristics which are characterized as pseudoprogression [20]

Summary

Introduction

Glioblastoma (GBM) is the most malignant primary brain tumor in adults with dismal prognosis [1]. During follow-up, radiotherapy and chemotherapy may produce new lesions that may mimic tumor progression or recurrence on imaging. Us, vascular damage has a critical role in the development of radiation-induced effects in the brain; further research is needed. Brades et al proposed that tumors with methylation of the MGMT promoter, due to greater effect of the combination of temozolomide and radiotherapy to residual tumor, produce a temporary worsening of imaging characteristics which are characterized as pseudoprogression [20]. There is a reduction in the degree of enhancement by the tumor and a decrease in the surrounding edema on fluid-attenuated inversion recovery (FLAIR) Such an imaging appearance, which imitates a favorable treatment response, is termed “pseudoresponse” because this is due to alterations in vascular permeability instead of tumor response to treatment. There might be a rebound effect later with the presence of enhancement and edema [24, 25]

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