CNS Tumors: PET/CT and MRI for Response Assessment of CNS Tumors Following Immunotherapy
Immunotherapy with checkpoint inhibitors has determined a big impact on patient management in the last decade, leading to unpreceded durable responses to treatment. The peculiarities of the CNS and its supposed “isolation” from the immune system have limited for long time the implementation of these immunotherapeutic agents in patients with primary brain tumors or brain metastases. Recent discoveries and the promising preclinical findings in glioblastoma have encouraged the research and implemented the use of checkpoint inhibitors, vaccines, and other immune-modulating drugs in clinical trials. New therapeutic regimens are frequently followed by the requirement of new criteria for response assessment. The iRANO (Immunotherapy RANO) criteria have been introduced consequently, although challenges in differentiating progression from pseudoprogression persist. Metabolic response with PET can provide useful information in this context and help perform a proper response assessment. In the following sessions, some examples of primary and metastatic brain tumors treated with immunotherapy are shown together with corresponding morphological and metabolic imaging findings.
KeywordsMalignant glioma Brain tumors Metastases Immunotherapy Vaccines Response assessment
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