Advances in clinical neuro-oncology research on integrin PET imaging

Angiogenesis plays a pivotal role in the progression of neuro-oncological diseases, mediated by integrin receptors on endothelial and tumor cells. Radiolabeled RGD peptides, targeting integrins such as αvβ₃, offer potential as imaging tracers for diagnosing and monitoring these diseases. This review evaluates the effectiveness and reliability of RGD-containing peptides for PET imaging in neuro-oncology, focusing on diagnostic performance, tumor delineation, and treatment response evaluation.

A systematic literature search was conducted in PubMed, EMBASE, and Cochrane Library until November 2024, identifying relevant studies using RGD-based tracers in neuro-oncological imaging. Data on patient demographics, tumor types, imaging protocols, tracer characteristics, and outcomes were extracted. Methodological quality was assessed using the QUADAS-2 tool.

Eight studies, encompassing 112 patients with primary and secondary brain tumors, were included. All studies utilized αvβ₃ integrin expression-targeting RGD PET tracers. Compared to [¹⁸F]FDG PET, RGD-targeted imaging demonstrated superior tumor-to-background ratios, enabling better detection of neuro-oncological lesions. Only a limited number of studies included histopathological validation, which revealed a strong correlation between integrin expression and tracer uptake. RGD-based imaging also predicted treatment response to chemoradiotherapy and bevacizumab, with significant SUVmax reductions linked to better prognoses. No adverse events related to radiotracers were reported. However, since RGD PET tracers do not cross the blood-brain barrier, the extent to which nonspecific accumulation occurs due to blood-brain barrier disruption in neuro-oncological disease remains partially elusive.

RGD PET imaging is a promising tool for neuro-oncology, providing enhanced diagnostic accuracy and valuable prognostic insights. Future research should focus on integrating molecular imaging findings into personalized treatment strategies and exploring novel RGD tracers for broader clinical applications.