PET-imaging for treatment response evaluation in brain metastasis: a systematic review and meta-analysis

radiotherapy PET Brain metastasis

dr. A van der Hoorn
C.W. Govaerts

Type of project:
Pilot project (year 2 or 3)

Nature of the research:
Our group previously published a systematic review and meta-analysis on the efficacy of multimodal MRI techniques for treatment response evaluation in brain metastases [1]. This was in order to evaluate the diagnostic accuracy of both conventional and experimental MRI to differentiate between pseudoprogression and true tumour progression after focal radiation, an important clinical dilemma in neuro-oncology. We intend to expand from this work by evaluating the utility of PET-imaging for the same clinical question. Conducting this study will involve, as the title suggests, a systematic appraisal of the literature and compiling studies that match our selection criteria to perform a meta-analysis. We were hoping to enlist a motivated student to contribute to this work.

Fields of study:
oncology radiology nuclear medicine

Background / introduction
Brain metastases are the most common type of intracranial neoplasm and are an increasingly large burden in oncology. Treatment of brain metastases is multifaceted, but the mainstay of therapy is focal radiation with stereotactic radiosurgery. A common clinical dilemma during treatment follow-up with MRI are changes in contrast enhancement in the irradiated region of brain that mimic true tumour progression but in fact arise as a result of benign inflammatory processes and blood-brain-barrier disruption. This phenomenon is termed ‘pseudoprogression’, and makes the decision about whether to re-initiate treatment or adopt a conservative approach very challenging. Conventional MRI is poor in the differentiation of tumour progression with pseudoprogression, necessitating the use of more advanced imaging techniques for response evaluation. PET-imaging has been widely used for this application, but an up-to-date pooled analysis of the literature to reliably judge the effectiveness of different PET-tracers is lacking. We hope to address this gap with the here described study.
Research question / problem definition
Which PET-technique has the greatest combined sensitivity and specificity to distinguish pseudoprogression from true progressive disease in brain metastases treated with focal radiation?
- Generation of a search strategy for Embase, Medline, Web of Science, Cochrane and Google Scholar in cooperation with the central-medical library (CMB) of the RuG
- Deduplication of identified articles
- Title and abstract screening for initial inclusion by two readers
- Full text assessment of screened studies for matching to inclusion criteria
- Quality assessment of included studies
- Calculating pooled sensitivity and specificity values per included PET-tracer for the diagnosis of true tumour progression vs pseudoprogression
- Writing the manuscript
1. Teunissen WHT, Govaerts CW, Kramer MCA, Labrecque JA, Smits M, Dirven L, et al. Diagnostic accuracy of MRI techniques for treatment response evaluation in patients with brain metastasis: A systematic review and meta-analysis. Radiother Oncol. 2022;177: 121–33.
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