Nimg-47pathologically Confirmed Viable Tumor Surrounds Regions of Progressively Expanding Diffusion-restricted Necrosis Following Bevacizumab Treatment
Year: 2015
Type: article
Study design: Case Report
Abstract: INTRODUCTION: In a subset of recurrent glioblastoma patients, bevacizumab has been shown to induce regions of diffusion restriction. Previous conflicting reports have found that these lesions contain either hypercellular tumor or diffusion restricted necrosis. This study uses whole brain samples to determine both the histological characteristics of the diffusion restricted lesions, and the surrounding tissue. METHODS: Seven patients with bevacizumab induced diffusion restricted lesions were recruited for brain donation for this study. The patient's brains were sectioned in the same axial orientation as their final clinical imaging session using individualized custom 3d-printed slicing jigs. Clinical imaging acquired prior to death included diffusion weighted imaging (DWI), T1 pre and post gadolinium contrast, and T2 weighted images. Apparent diffusion coefficient (ADC) maps were calculated from the DWI. Diffusion restriction was defined using radiological criteria. All regions were outside of contrast enhancement, yet within T2 hyperintensity. Specimens were acquired from the brain slice and region that co-localized with the diffusion restriction. Samples were then paraffin embedded, H&E stained, and digitized for interpretation. Each sample was the read by our pathologist to differentiate necrotic regions from viable tumor. RESULTS: In six of seven patients, the diffusion-restricted lesions were progressively growing at the time of the patient's final scan. In all cases, the diffusion restriction was co-localized to necrotic tissue. In the six progressing patients, the diffusion-restricted necrosis was surrounded by viable hypercellular non-enhancing tumor. The patient without progressively growing diffusion restriction had recurrent tumor elsewhere, not directly adjacent to the diffusion restriction. CONCLUSION: We pathologically confirmed that progressively growing diffusion restriction in patients undergoing bevacizumab treatment indicated necrosis surrounded by viable hypercellular tumor. This information should be considered when choosing to continue or withdraw bevacizumab therapy.
Source: Neuro-Oncology
Institution: Medical College of Wisconsin
Language: English
Subfield: Genetics
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2412607125