In Danish guidelines for imaging of patients with prostate cancer and PSA
relapse, PSMA PET/CT is the recommended restaging modality. A multicenter study
has been initiated to analyze findings of 68Ga-PSMA PET/CT scans for patients with
prostate cancer with PSA relapse. This report details preliminary findings of 779
patients in six cohorts from three continents. At the time of the restaging, the PSA
values were grossly similar between the six cohorts, with an important subgroup of the
patients having PSA values < 1 ng/ml. Patients who initially underwent radical
prostatectomy had lower PSA values at the restaging than patients who were initially
treated with external beam radiation therapy or brachytherapy. Even for patients with
restaging PSA values < 0.5 ng/ml, some patients had positive sites in extra pelvic
lymph nodes and bones. Patients were followed up to 7 years after the restaging PSMA
PET/CT. In multiple Cox regression analysis of 196 patients, only the number of
positive sites on 68Ga-PSMA PET/CT significantly predicted overall survival (p =
0.0001). The findings illustrate why restaging PSMA PET/CT change salvage
treatment for up to half of the patients with PSA relapse compared with planned
salvage treatment based on only conventional imaging modalities like CT and bone
scans.
Keywords: PET/CT, Prostate cancer: prostate specific membrane antigen, Restaging.
