Pseudoprogression after glioma therapy: an update

ABSTRACT

Introduction: Initial diagnostics and follow-up of gliomas is usually based on contrast-enhanced MRI. However, the capacity of standard MRI to differentiate neoplastic tissue from posttherapeutic effects such as pseudoprogression is limited. Advanced neuroimaging methods may provide relevant additional information, which allow for a more accurate diagnosis especially in clinically equivocal situations. This review article focuses predominantly on PET using radiolabeled amino acids and advanced MRI techniques such as perfusion-weighted imaging (PWI) and summarizes the efforts of these methods regarding the identification of pseudoprogression after glioma therapy.

Areas covered: The current literature on pseudoprogression in the field of brain tumors, with a focus on gliomas is summarized. A literature search was performed using the terms ‘pseudoprogression’, ‘temozolomide’, ‘glioblastoma’, ‘PET’, ‘PWI’, ‘radiochemotherapy’, and derivations thereof.

Expert commentary: The present literature provides strong evidence that PWI MRI and amino acid PET can be of great value by providing valuable additional diagnostic information in order to overcome the diagnostic challenge of pseudoprogression. Despite various obstacles such as the still limited availability of amino acid PET and the lack of standardization of PWI, the diagnostic improvement probably results in relevant benefits for brain tumor patients and justifies a more widespread use of these diagnostic tools.

KEYWORDS:

• FET PET
• advanced MRI
• PWI
• temozolomide
• glioblastoma
• immunotherapy
• checkpoint inhibitors

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.

Additional information

Funding

This work was supported by the Wilhelm-Sander Stiftung, Germany.