PSMA- and GRPR-Targeted PET: Results from 50 Patients with Biochemically Recurrent Prostate Cancer

J Nucl Med. 2021 Nov;62(11):1545-1549. doi: 10.2967/jnumed.120.259630. Epub 2021 Mar 5.

Abstract

Novel radiopharmaceuticals for PET are being evaluated for the diagnosis of biochemical recurrence (BCR) of prostate cancer (PC). We compared the gastrin-releasing peptide receptor-targeting 68Ga-RM2 with the prostate-specific membrane antigen (PSMA)-targeting 68Ga-PSMA11 and 18F-DCFPyL. Methods: Fifty patients underwent both 68Ga-RM2 PET/MRI and 68Ga-PSMA11 (n = 23) or 18F-DCFPyL (n = 27) PET/CT at an interval ranging from 1 to 60 d (mean ± SD, 15.8 ± 17.7 d). SUVmax was collected for all lesions. Results:68Ga-RM2 PET was positive in 35 and negative in 15 of the 50 patients. 68Ga-PSMA11/18F-DCFPyL PET was positive in 37 and negative in 13 of the 50 patients. Both scans detected 70 lesions in 32 patients. Forty-three lesions in 18 patients were identified on only 1 scan: 68Ga-RM2 detected 7 more lesions in 4 patients, whereas 68Ga-PSMA11/18F-DCFPyL detected 36 more lesions in 13 patients. Conclusion:68Ga-RM2 remains a valuable radiopharmaceutical even when compared with the more widely used 68Ga-PSMA11/18F-DCFPyL in the evaluation of BCR of PC. Larger studies are needed to verify that identifying patients for whom these 2 classes of radiopharmaceuticals are complementary may ultimately allow for personalized medicine.

Trial registration: ClinicalTrials.gov NCT02624518 NCT02673151 NCT03501940.

Keywords: 18F-DCFPyL; 68Ga-PSMA11; 68Ga-RM2; PET; prostate cancer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Humans
  • Male
  • Middle Aged
  • Positron Emission Tomography Computed Tomography
  • Prostatic Neoplasms*
  • Receptors, Bombesin

Substances

  • Receptors, Bombesin

Associated data

  • ClinicalTrials.gov/NCT02624518
  • ClinicalTrials.gov/NCT02673151
  • ClinicalTrials.gov/NCT03501940