Glioma recurrence versus radiation necrosis: accuracy of current imaging modalities

Abstract

Treatment for brain gliomas is a combined approach of surgery, radiation therapy and chemotherapy. Nevertheless, high-grade gliomas usually recur despite treatment. Ionizing radiation therapy to the central nervous system may cause post-radiation damage. Differentiation between post-irradiation necrosis and recurrent glioma on the basis of clinical signs and symptomatology has not been possible. Computed tomography (CT) and magnetic resonance imaging (MRI) suffer from significant limitations when applied to differentiate recurrent brain tumor from radiation necrosis. We reviewed the contribution of recent MRI techniques, single-photon emission CT and positron emission tomography to discriminate necrosis for glioma recurrence. We concluded that despite the progress being made, further research is needed to establish reliable imaging modalities that distinguish between true tumour progression and treatment-related necrosis.

Diagnostic Accuracy of PET for Recurrent Glioma Diagnosis: A Meta-Analysis

“…Furthermore, most studies retrospectively and jointly assessed low-and high-grade gliomas treated with heterogeneous treatment strategies and adopted heterogeneous methodologies for confirming disease relapse with diverse follow-up protocols. Our findings expand the findings of previous narrative reviews 9,44 by providing a quantitative overview of the diagnostic accuracy of PET for differentiating between disease recurrence and treatment-induced changes. Additionally, our work provides a comprehensive review of studies directly comparing different PET tracers and those comparing PET with alternative imaging tests in this clinical setting.…”

In vivo chemical exchange saturation transfer imaging allows early detection of a therapeutic response in glioblastoma

“…In radiological monitoring, it is difficult to assess tumor progression or treatment response because there are several types of treatment-related "reactions" that occur immediately to late after surgical resection or radiation therapy, especially concurrent with TMZ (24,25). These tissue reactions, referred to as "pseudoprogression," have similar imaging characteristics as actual tumor, so it is difficult to differentiate between true tumor progression and pseudoprogression by use of conventional MR methods (26,27). Thus, the neurooncology treatment team must rely on "best-guess" histories based on clinical context.…”

Characterization of pseudoprogression in patients with glioblastoma: Is histology the gold standard?

“…Its importance lies in the fact that it can be indistinguishable on routine noninvasive imaging techniques from early recurrent tumor which portends a very poor prognosis. Advanced imaging methods show promise in diagnosis and differentiation between tumor recurrence versus radiation necrosis [25][26][27][28] and psPD, [29][30][31][32][33] but are not yet validated. In cases where surgical sampling is decided upon, careful pre-surgical planning and close communication between team members is essential.…”