Advanced Imaging Techniques for Differentiating Pseudoprogression and Tumor Recurrence After Immunotherapy for Glioblastoma

Abstract

Glioblastoma (GBM) is the most common malignant tumor of the central nervous system with poor prognosis. Although the field of immunotherapy in glioma is developing rapidly, glioblastoma is still prone to recurrence under strong immune intervention. The major challenges in the process of immunotherapy are evaluating the curative effect, accurately distinguishing between treatment-related reactions and tumor recurrence, and providing guidance for clinical decision-making. Since the conventional magnetic resonance imaging (MRI) is usually difficult to distinguish between pseudoprogression and the true tumor progression, many studies have used various advanced imaging techniques to evaluate treatment-related responses. Meanwhile, criteria for efficacy evaluation of immunotherapy are constantly updated and improved. A standard imaging scheme to evaluate immunotherapeutic response will benefit patients finally. This review mainly summarizes the application status and future trend of several advanced imaging techniques in evaluating the efficacy of GBM immunotherapy.

Malignant Mimics of Trigeminal Schwannoma

“…Advanced imaging modalities may be useful for distinguishing between tumor progression and pseudoprogression, 5 including perfusion MRI and magnetic resonance spectroscopic imaging. 6 Nuclear imaging such as [ 18 F]fluorothymidine positron emission tomography may also have a role in differentiating active tumor from radionecrosis. 7 Finally, traditional MRI sequences may be insufficient to distinguish between common and uncommon entities arising from cranial nerves.…”

Conventional and Advanced Imaging Techniques in Post-treatment Glioma Imaging

“…Glioma tumor biology is marked by neovascularization with resultant tumor progression and therapy resistance (2,8,9). Specifically, tumor cells are prone to infiltration of the normal brain parenchyma with remnant tumor stem cells after resection and CRT, which is a source of tumor recurrence (2,(8)(9)(10).…”

“…Glioma tumor biology is marked by neovascularization with resultant tumor progression and therapy resistance (2,8,9). Specifically, tumor cells are prone to infiltration of the normal brain parenchyma with remnant tumor stem cells after resection and CRT, which is a source of tumor recurrence (2,(8)(9)(10). Tumor heterogeneity is a hallmark of gliomas in the post-treatment setting as there is often an admixture of treated and viable tumor cells and treatment-induced necrosis (8,11).…”

“…Specifically, tumor cells are prone to infiltration of the normal brain parenchyma with remnant tumor stem cells after resection and CRT, which is a source of tumor recurrence (2,(8)(9)(10). Tumor heterogeneity is a hallmark of gliomas in the post-treatment setting as there is often an admixture of treated and viable tumor cells and treatment-induced necrosis (8,11). Gliomaassociated vessels demonstrate marked spatial heterogeneity, and the marginal tumor area consists of proliferative and invasive cells with increased microvascular density and active angiogenesis (2,9).…”

Development of a low-grade glioma in an ischemic brain territory that evolved into a glioblastoma. A case report and brief literature review

“…Glioblastoma is the most common and rapidly growing primary malignancy of the brain; it has a very poor prognosis despite continuous improvements in diagnostic and therapeutic strategies in recent years. MRI is widely used in the diagnosis and postoperative management of patients with glioblastoma [1]. Despite aggressive multimodal treatment, the prognosis of this neoplasm remains poor.…”