Abstract
Brain metastases are a major clinical problem, and immunotherapy offers a novel treatment paradigm with the potential to synergize with existing focal therapies like surgery and radiosurgery or even replace them in future. The brain is a unique microenvironment structurally and immunologically. The immune response is likely to be crucial to the adaptation of systemic immune modulating agents against this disease. Imaging is frequently employed in the clinical diagnosis and management of brain metastasis, so it is logical that brain imaging techniques are investigated as a source of biomarkers of the immune response in these tumors. Current imaging techniques in clinical use include structural MRI (post-contrast T1W sequences, T2, and FLAIR), physiological sequences (perfusion- and diffusion-weighted imaging), and molecular imaging (MR spectroscopy and PET). These are reviewed for their application to predicting and measuring the response to immunotherapy in brain metastases.
Highlights
The overall clinical burden from brain metastases (BM) is increasing, most likely to due to more widespread use of brain imaging, even in asymptomatic patients, and improved control of extracranial disease and survival in cancers that predispose to BM
There is a clear need for further investigation of imaging biomarkers of immunotherapy in BM; these may develop along with extracranial imaging techniques for assessing other metastases or arise from the existing intracranial techniques for
Used in clinical practice, large amount of data on relation of perfusion to BM including from different primaries, high spatial resolution
Summary
The overall clinical burden from brain metastases (BM) is increasing, most likely to due to more widespread use of brain imaging, even in asymptomatic patients, and improved control of extracranial disease and survival in cancers that predispose to BM. A number of trials of ICI for solid organ cancers that have included patients with BM suggest a heterogeneous but robust response in the brain [(2) summary [3], for specific example in metastatic melanoma]. This has come on the background of increased investigation of the BM microenvironment and the understanding that this is an immunologically distinct rather than immune-isolated compartment [4, 5]. At the time of writing this report, there was insufficient data in this field for a systematic review applying PRISMA [10] guidelines; we have performed a narrative review and categorized the clinically available techniques in brain imaging—taking in studies from other brain tumors and therapies—to assess the prospects for the development of biomarkers of response to immunotherapy in BM
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
