Avastin Scintigraphy in Surveillance of Bevacizumab Treatment in a Patient with Neurofibromatosis Type 2: A Case Report

A patient with neurofibromatosis type 2 (bilateral vestibular schwannomas) was treated with bevacizumab (antivascular endothelial growth factor [VEGF] monoclonal antibody). The left-sided tumor showed intense uptake on pretreatment. (111)In-bevacizumab scintigraphy, indicating VEGF production in the tumor, and no uptake 4 weeks later, demonstrated effective binding of nonradiolabeled bevacizumab to the VEGF produced in the tumor. The right-sided tumor showed no tracer uptake at any time point. Significant tumor volume reduction (assessed with MRI) and hearing improvement were observed on the left side. (111)In-bevacizumab scintigraphy may be a promising upfront patient selection tool to identify patients who may benefit from expensive bevacizumab treatment.