In this study, published in The Lancet Oncology, we sought to evaluate the diagnostic performance of the gastrin-releasing peptide receptor (GRPR) antagonist 68Ga-RM2 in 100 patients with elevated PSA but inconclusive conventional imaging findings.
The results were promising: 68Ga-RM2 PET/MRI showed a significantly higher detection rate, sensitivity, and negative predictive value compared to MRI alone. Specificity and positive predictive value were equally high between both modalities. Notably, GRPR-targeted PET/MRI outperformed MRI consistently across different PSA concentrations, particularly at low PSA levels.
While PSMA-targeted PET imaging remains widely used, GRPR-targeted PET imaging shows potential as a complementary or alternative approach. Moreover, radiolabeled with the beta emitter 177Lu or the alpha emitter 225Ac, GRPR can also serve as a target for theragnostic applications, offering a promising avenue for personalized treatment strategies.
This study represents a significant step forward in the quest for more accurate imaging modalities for recurrent prostate cancer. Further research is needed to validate these findings and explore the clinical implications of GRPR-targeted PET imaging in guiding treatment decisions and improving patient outcomes.
Written by: Heying Duan,1 Farshad Moradi,1 Guido A Davidzon,1 Tie Liang,1 Hong Song,1 Andreas M Loening,2 Shreyas Vasanawala,2 Sandy Srinivas,3 James D Brooks,4 Steven Hancock,5 Andrei Iagaru1
- Department of Radiology, Division of Nuclear Medicine and Molecular Imaging, Stanford University, Stanford, CA, USA.
- Department of Radiology, Division of Body MRI, Stanford University, Stanford, CA, USA.
- Department of Medicine, Division of Oncology, Stanford University, Stanford, CA, USA.
- Department of Urology, Stanford University, Stanford, CA, USA.
- Department of Radiation Oncology, Stanford University, Stanford, CA, USA.