Abstract
PurposeMultiparametric magnetic resonance imaging (mpMRI) is a well-established imaging method for localizing primary prostate cancer (PCa) and for guiding targeted prostate biopsies. [18F]DCFPyL positron emission tomography combined with MRI (PSMA-PET/MRI) might be of additional value to localize primary PCa. The aim of this study was to assess the diagnostic performance of [18F]DCFPyL-PET/MRI vs. mpMRI in tumour localization based on histopathology after robot-assisted radical-prostatectomy (RARP), also assessing biopsy advice for potential image-guided prostate biopsies.MethodsThirty prospectively included patients with intermediate to high-risk PCa underwent [18F]DCFPyL-PET/MRI and mpMRI prior to RARP. Two nuclear medicine physicians and two radiologists assessed tumour localization on [18F]DCFPyL-PET/MRI and on mpMRI respectively, and gave a prostate biopsy advice (2 segments) using a 14-segment model of the prostate. The uro-pathologist evaluated the RARP specimen for clinically significant PCa (csPCa) using the same model. csPCa was defined as any PCa with Grade Group (GG) ≥ 2. The biopsy advice based on imaging was correlated with the final histology in the RARP specimen for a total-agreement analysis. An additional near-agreement correlation was performed to approximate clinical reality.ResultsOverall, 142 of 420 (33.8%) segments contained csPCa after pathologic examination. The segments recommended for targeted biopsy contained the highest GG PCa segment in 27/30 patients (90.0%) both for [18F]DCFPyL-PET/MRI and mpMRI. Areas under the receiver operating characteristics curves (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the total-agreement detection of csPCa per segment using [18F]DCFPyL-PET/MRI were 0.70, 50.0%, 89.9%, 71.7%, and 77.9%, respectively. These results were 0.75, 54.2%, 94.2%, 82.8%, and 80.1%, respectively, for mpMRI only.ConclusionBoth [18F]DCFPyL-PET/MRI and mpMRI were only partly able to detect csPCa on a per-segment basis. An accurate detection (90.0%) of the highest GG lesion at patient-level was observed when comparing both [18F]DCFPyL-PET/MRI and mpMRI biopsy advice with the histopathology in the RARP specimen. So, despite the finding that [18F]DCFPyL-PET/MRI adequately detects csPCa, it does not outperform mpMRI.
Highlights
The diagnostic work-up of patients with an elevated prostate-specific antigen (PSA)-level and an increased risk of prostate cancer (PCa) is continuously changing [1]
A total of 30 patients was included in this study, and all patients were scheduled for robotassisted radical-prostatectomy (RARP) after [ 18F]DCFPyL positron emission tomography (PET)/ MRI and same-day multiparametric magnetic resonance imaging (mpMRI)
The diagnostic accuracy of both [18F]DCFPyL PET/MRI and mpMRI imaging was compared for the ability to localize and stage clinically significant PCa (csPCa) within the prostate gland and to guide potential targeted prostate biopsies
Summary
The diagnostic work-up of patients with an elevated prostate-specific antigen (PSA)-level and an increased risk of prostate cancer (PCa) is continuously changing [1]. The addition of multiparametric magnetic resonance imaging (mpMRI) of the prostate before prostate biopsy has been implemented in the guidelines by the European Association of Urology (EAU) [1]. In this systematic approach, prostate biopsies need to be combined with mpMRItargeted prostate biopsies (MRI-TBx) of radiologically abnormal regions within the prostate [3,4,5]. MpMRI assists in improving the yield of prostate biopsies for the diagnosis of clinically significant PCa (csPCa), and besides enhances local staging of PCa [6]. For planning EBRT, local staging is crucial for deciding on radiation dose and adjuvant therapies [6, 10]
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