Can an Emerging PET Radiotracer Enhance Detection of Prostate Cancer Recurrence?

New research suggests that targeting gastrin releasing peptide receptors (GRPRs) with ⁶⁸Ga-RM2 PET/MRI may significantly enhance the diagnosis of prostate cancer recurrence.

For the prospective phase II/III study, recently presented at the Radiological Society of North America (RSNA) conference, researchers compared ⁶⁸Ga-RM2 positron emission tomography (PET)/magnetic resonance imaging (MRI) vs. MRI alone in 100 men with a post-prostatectomy prostate specific antigen (PSA) level > 0.2 ng/mL or a PSA level > above nadir after radiotherapy.

Findings from the research revealed that ⁶⁸Ga-RM2 PET/MRI had an 85.2 percent sensitivity rate for diagnosing biochemical recurrence of prostate cancer in comparison to a 49.4 percent sensitivity rate for MRI alone.

While both modalities offered comparable specificity at 100 percent, 68Ga-RM2 PET/MRI had an 85.2 percent sensitivity rate for diagnosing biochemical recurrence of prostate cancer in comparison to a 49.4 percent sensitivity rate for MRI alone.

While both modalities offered comparable specificity at 100 percent, use of ⁶⁸Ga-RM2 PET/MRI led to a significantly higher detection of prostate cancer lesions (143 vs. 96 for MRI alone), according to the research, which was awarded with the RSNA 2023 Trainee Research Prize in the Nuclear Medicine and Molecular Imaging category

Noting that GRPRs are overexpressed in prostate cancer, study author Heying Duan, M.D., M.B.A, said ⁶⁸Ga-RM2 PET/MRI may prove to be a viable option for diagnosing and facilitating timely intervention for biochemical recurrence of prostate cancer.

“The collective findings of this comparative imaging trial and other published studies provide compelling evidence that ⁶⁸Ga-RM2 PET/MRI not only outperforms conventional imaging with MRI but also shows higher reliability and number of lesions detected, which could potentially affect subsequent patient management,” wrote Dr. Duan, a postdoctoral research fellow at the Stanford University School of Medicine.

Reference

1. Duan H, Moradi F, Davidzon GA, et al. Final analysis of a prospective, single-center, phase II/III imaging trial of 68Ga-RM2 PET/MRI in patients with biochemical recurrence of prostate cancer. Presented at the RSNA 2023 109th Scientific Assembly and Annual Meeting Nov. 26-30, 2023. Available at https://www.rsna.org/annual-meeting . Accessed December 13, 2023.

(Editor’s note: For related content, see “Seven Takeaways from Meta-Analysis of PSMA Radiotracers for Prostate Cancer Imaging,” “Emerging Insights in Diagnosing Recurrent Prostate Cancer in Men with Low PSA Levels” and “Can an Emerging PET Radiotracer be a Viable Alternative to Multiparametric MRI for Detecting Prostate Cancer Recurrence?”)