68Ga-RM2 PET-MRI Versus MRI Alone for Evaluation of Patients with Biochemical Recurrence of Prostate Cancer: A Single-Centre, Single-Arm, Phase 2/3 Imaging Trial - Beyond the Abstract

Prostate cancer poses a significant health concern globally. Early detection of recurrence is key to effective treatment and patient management. Conventional imaging methods like CT and MRI often fall short in accurately localizing recurrent tumors, especially at low prostate-specific antigen (PSA) concentrations.

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

  1. Department of Radiology, Division of Nuclear Medicine and Molecular Imaging, Stanford University, Stanford, CA, USA.
  2. Department of Radiology, Division of Body MRI, Stanford University, Stanford, CA, USA.
  3. Department of Medicine, Division of Oncology, Stanford University, Stanford, CA, USA.
  4. Department of Urology, Stanford University, Stanford, CA, USA.
  5. Department of Radiation Oncology, Stanford University, Stanford, CA, USA.
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