Pelvic lymph-node staging with 18F-DCFPyL PET/CT prior to extended pelvic lymph-node dissection in primary prostate cancer - the SALT trial

• Published in: European journal of nuclear medicine and molecular imaging 2021-02, Vol.48 (2), p.509-520
• Main Authors: Jansen, B. H. E., Bodar, Y. J. L., Zwezerijnen, G. J. C., Meijer, D., van der Voorn, J. P., Nieuwenhuijzen, J. A., Wondergem, M., Roeleveld, T. A., Boellaard, R., Hoekstra, O. S., van Moorselaar, R. J. A., Oprea-Lager, D. E., Vis, A. N.
• Format: Article
• Language: English
• Subjects: Antigens; Cancer surgery; Cardiology; Computed tomography; Confidence intervals; Diagnostic systems; Dissection; Fluorine isotopes; Imaging; Lymph; Magnetic resonance imaging; Medical imaging; Medicine; Medicine & Public Health; Metastases; Metastasis; Nodes; Nomograms; Nuclear Medicine; Oncology; Oncology – Genitourinary; Original; Original Article; Orthopedics; Physicians; Positron emission; Prostate cancer; Prostatectomy; Radiology; Robots; Sensitivity; Statistical analysis; Tomography; Tracers; Urological surgery
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-020-04974-w

Purpose The detection of lymph-node metastases (N1) with conventional imaging such as magnetic resonance imaging (MRI) and computed tomography (CT) is inadequate for primarily diagnosed prostate cancer (PCa). Prostate-specific membrane antigen (PSMA) PET/CT is successfully introduced for the staging of (biochemically) recurrent PCa. Besides the frequently used 68 gallium-labelled PSMA tracers, 18 fluorine-labelled PSMA tracers are available. This study examined the diagnostic accuracy of 18 F-DCFPyL (PSMA) PET/CT for lymph-node staging in primary PCa. Methods This was a prospective, multicentre cohort study. Patients with primary PCa underwent 18 F-DCFPyL PET/CT prior to robot-assisted radical prostatectomy (RARP) with extended pelvic lymph-node dissection (ePLND). Patients were included between October 2017 and January 2020. A Memorial Sloan Kettering Cancer Centre (MSKCC) nomogram risk probability of ≥ 8% of lymph-node metastases was set to perform ePLND. All images were reviewed by two experienced nuclear physicians, and were compared with post-operative histopathologic results. Results A total of 117 patients was analysed. Lymph-node metastases (N1) were histologically diagnosed in 17/117 patients (14.5%). The sensitivity, specificity, positive predictive value and negative predictive value for the 18 F-DCFPyL PET/CT detection of pelvic lymph-node metastases on a patient level were 41.2% (confidence interval (CI): 19.4–66.5%), 94.0% (CI 86.9–97.5%), 53.8% (CI 26.1–79.6%) and 90.4% (CI 82.6–95.0%), respectively. Conclusion 18 F-DCFPyL PET/CT showed a high specificity (94.4%), yet a limited sensitivity (41.2%) for the detection of pelvic lymph-node metastases in primary PCa. This implies that current PSMA PET/CT imaging cannot replace diagnostic ePLND. Further research is necessary to define the exact place of PSMA PET/CT imaging in the primary staging of PCa.