Assessment of Target Volume Definition for Irradiation of Hemangiopericytomas: An Original Article

Background: Hemangiopericytomas arise from the mesenchymal cells with pericytic differentiation. Clinical course of these rare tumors may be aggressive with high propensity for local recurrence and metastases. Radical resection is the treatment of choice for lesions amenable to surgery. Nevertheless, radiation therapy (RT) may have a role in management of hemangiopericytomas either as an adjunctive, salvage or primary treatment, or for palliation of metastases in selected patients. Target volume definition is a critical aspect of RT. Objective: Aim of this study is to assess incorporation of multimodality imaging with magnetic resonance imaging (MRI) into target volume definition for irradiation of hemangiopericytomas. Methods: In this study, treatment volume definition with multimodality imaging by incorporating MRI or by use of computed tomography (CT)-simulation images only was comparatively evaluated for patients with hemangiopericytoma. Results: Ground truth target volume defined by the board-certified radiation oncologists following meticulous evaluation, colleague peer review, collaboration, and ultimate consensus was found to be identical with target determination based on CT-MR fusion based imaging in this study. Conclusion: Accurate target volume determination is an indispensable part of RT for management of hemangiopericytomas. Incorporation of MRI in the target volume definition process may be considered for optimization of treatment volume designation for successful RT applications. Clearly, future studies are required to shed light on this issue.