Regional Lymph Node Metastasis on Prostate Specific Membrane Antigen Positron Emission Tomography Correlates with Decreased Biochemical Recurrence-Free and Therapy-Free Survival after Radical Prostatectomy: A Retrospective Single-Center Single-Arm Observational Study.

PURPOSE: We sought to address the impact of preoperative prostate specific membrane antigen (PSMA) positron emission tomography (PET) findings prior to radical prostatectomy and pelvic lymph node dissection on biochemical recurrence and time to adjuvant or salvage treatment. MATERIALS AND METHODS: Between 2013 and 2017, 64 intermediate and 166 high risk (230) prostate cancer patients received 68Ga-PSMA-11 PET followed by radical prostatectomy and pelvic lymph node dissection. Biochemical recurrence-free and therapy-free survivalwere determined. For all time-to-event analyses, univariable and multivariable Cox proportional hazards models and univariable Kaplan-Meier analyses were applied, with a significance threshold of p <0.05. RESULTS: The overall sensitivity, specificity, positive predictive value and negative predictive value of PSMA PET for pN1 disease was 48.5%, 95.7%, 82.1% and 82.2%, respectively. Median followup was 30.2 months. Biochemical recurrence occurred in 50.4% (116) of patients and adjuvant or salvage treatment was performed in 46.5% (107). Worst biochemical recurrence-free and therapy-free survival was observed in pN1 patients who also exhibited PSMA PET positive lymph node, followed by pN1 patients without PSMA PET positive lymph node and patients without evidence of lymph node metastasis on histology and PSMA PET (median biochemical recurrence-free survival 1.7 vs. 7.5 vs. >36 months, median therapy-free survival 2.6 vs. 8.9 vs. >36 months). CONCLUSIONS: Patients with positive lymph node on PSMA PET prior to radical prostatectomy have to expect early biochemical recurrence and adjuvant/salvage therapy, despite thorough pelvic lymph node dissection. Therefore, results from PSMA PET can be used for patients' consultation and more stringent followup as well as for planning of neoadjuvant/adjuvant therapy.

[68Ga-PSMA-11 PET/mpMRI for local detection of primary prostate cancer in men with a negative prior biopsy]. / 68Ga-PSMA-11 PET/mpMRT zur Lokaldetektion des primären Prostatakarzinom bei Männern mit negativer Vorbiopsie.

INTRODUCTION AND OBJECTIVE: Multiparametric MRI (mpMRI) 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 68Ga-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 68Ga-PSMA-11 PET/mpMRI imaging of the prostate. mpMRI was evaluated according to the PIRADS classification system and 68Ga-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 68Ga-PSMA-11 PET/mpMRI 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 68Ga-PSMA-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, 68Ga-PSMA-11 PET and mpMRI show partially complementary findings that enhance the detection of PC lesions.

Detection efficacy of 18F-rhPSMA-7.3 PET/CT and impact on patient management in patients with biochemical recurrence of prostate cancer after radical prostatectomy and prior to potential salvage treatment.

Purpose: Radiohybrid prostate-specific membrane antigen (rhPSMA) ligands are a new class of 18F-labeled PSMA-targeting agents. 18F-rhPSMA-7.3 is a lead compound which is currently under investigation in two multicenter phase III trials for PET-imaging. Here, we report the first retrospective data on its detection efficacy and potential impact on clinical management in a homogeneous cohort of patients with biochemical recurrence after radical prostatectomy, and prior to any salvage therapy. Methods: 242 patients (median [range] PSA, 0.60 [0.2-60.8] ng/mL) who underwent 18F-rhPSMA-7.3 PET/CT were retrospectively selected from the institutions' database. Images were re-read by an experienced nuclear medicine physician. Lesion detection rates were stratified by PSA. Further, potential management before and after PET was assessed by an interdisciplinary simulated tumor board and categorized (major vs. minor vs. no therapeutic change). The distribution of management change identified in each PSA subgroup was determined. Results: In total, 176/242 (72.7%) patients showed PSMA-ligand positive findings. 18F-rhPSMA-7.3 detection rates were 61.8% (63/102), 67.9% (38/56), 81.1% (30/37) and 95.7% (45/47) for PSA-levels of 0.2-<0.5 ng/mL, 0.5-<1 ng/mL, 1-<2 ng/mL and ≥2 ng/mL, respectively. 18F-rhPSMA-7.3 PET/CT revealed local recurrence, pelvic lymph node metastases, retroperitoneal lymph nodes metastases, supradiaphragmatic lymph nodes, bone metastases, and visceral metastases in 48.8% (n = 118), 28.9% (n = 70), 6.6% (n = 16), 1.2% (n = 3), 13.2% (n = 32) and 1.2% (n = 3) of patients, respectively. Notably, bone lesions were identified in 8.8% of patients (9/102) with PSA <0.5 ng/mL. Results from the interdisciplinary simulated tumor board indicated change of therapeutic management in 153/242 patients (63.2%) with 54/242 (22.3%) considered major and 99/242 (40.9%) minor, respectively. 18F-rhPSMA-7.3 PET/CT did not prompt any therapeutic changes in 64/242 patients (26.4%). Conclusion: 18F-rhPSMA-7.3 PET offers high detection efficacy in patients with biochemical recurrence after radical prostatectomy, and prior to potential salvage therapy, and results in a potential change in treatment plans in nearly 2/3 of patients. Keywords: Biochemical recurrence; hybrid imaging; positron emission tomography; prostate cancer; prostate-specific membrane antigen.