68ga-Psma-11 Pet/Mpmri For Local Detection Of Primary Prostate Cancer In Men With A Negative Prior Biopsy

Introduction and objective Multiparametric MRI (mpMRl) represents the current gold standard for the detection of primary prostate cancer (PC) after a negative biopsy. PSMA PET imaging has been introduced in the diagnostic work-up of PC with high accuracy, but is currently mainly utilised in the setting of biochemical recurrence. This study aimed to determine the efficacy of combined Ga-68-PSMA-11 PET/mpMRI imaging to detect PC in patients with previously negative prostate biopsies.Methods A total of 57 patients who had undergone at least one prior negative prostate biopsy were included in this retrospective analysis. All patients underwent Ga-68-PSMA-11 PET/mpMRI imaging of the prostate. mpMRI was evaluated according to the PIRADS classification system and Ga-68-PSMA-11 PET was rated on a 5-point Likert scale (1: PC highly unlikely; 2: PC unlikely; 3: presence of PC is equivocal; 4: PC likely; 5: PC highly likely). All patients received a systematic random biopsy as well as a targeted transrectal biopsy of lesions suspicious on imaging. Imaging and histological biopsy outcomes were compared on a per-patient basis.Results In the histological analysis, 35/57 (61.4%) patients harboured PC lesions. In patients with biopsy-proven PC, 21/35 (60.0%) had a PI-RADS 4 or 5 lesion on mpMRI and 28/35 (80.0%) had a PET rating of 4 or 5. Combined (68)GaPSMA-11 PET/mpMRT missed only one patient with a Gleason score (GS) 7a tumour (rating of 1 or 2 in both PET and mpMRI). Limitations include the retrospective analysis as well as possible false negative biopsy results even in a fusion biopsy setting.Conclusion In this initial analysis, the combined (68)GaPSMA-11 PET/mpMRI proved to be a valuable imaging tool to guide prostate biopsies for the detection of PC in patients with a negative prior biopsy. In this approach, (68)GaPSMA-11 PET and mpMRI show partially complementary findings that enhance the detection of PC lesions.