#0196

Combined Prostate-specific Membrane Antigen Positron Emission Tomography (PSMA-PET) and multiparametric Magnetic Resonance Imaging (mpMRI) for the diagnosis of clinically significant prostate cancer (csPCa)

K. Chow¹, A. Lee Yuan Ming¹, D. peh², S. Thang³, Y. Law⁴, W. Lam Wing Chuen³, J. Yuen Shyi Peng¹, M. Hofman⁵, D. Murphy⁶, K. Chen¹

¹Singapore General Hospital, Department of Urology, Singapore, Singapore
²National Technological University, school of medicine, singapore, Singapore
³Singapore General Hospital, Department of Nuclear Medicine, singapore, Singapore
⁴Singapore General Hospital, Department of Diagnostic Radiology, singapore, Singapore
⁵Peter MacCallum Cancer Center, Theranostics and Imaging Centre of Excellence, Molecular Imaging and Therapeutic Nuclear Medicine, Melbourne, Australia
⁶Peter MacCallum Cancer Center, Department of Urology, Melbourne, Australia

Introduction:

only 11-15% of men with raised prostate specific antigen (PSA) are eventually diagnosed with clinically significant prostate cancer (csPCa) on prostate biopsy. An imaging modality that can accurately triage men with raised PSA is therefore necessary to reduce the number of unnecessary prostate biopsies performed. mpMRI is a viable pre-biopsy triaging tool but has limited specificity and positive predictive value (PPV). PSMA-PET can potentially complement mpMRI to more reliably exclude csPCa.

Material and methods:

A Diagnostic Test Accuracy (DTA) Systematic Review and Meta-Analysis (SRMA) was therefore performed to determine the diagnostic accuracy of combined imaging for csPCa detection with pairwise comparisons to mpMRI and PSMA-PET alone. Additionally, Decision Curve Analysis (DCA) compared the strategies of performing upfront biopsy versus combined imaging for suspected PCa patients, across varying thresholds for accepting the risk of missing a csPCa diagnosis. A search of PubMed, Embase, Central and Scopus databases, from inception to January 2024, was conducted. 19 studies (1969 patients) that referenced combined imaging against histopathology were included. Bivariate meta-analyses and meta-regression was performed to determine diagnostic parameters and assess differences between imaging modalities.

Results:

Combined imaging had a sensitivity, specificity, PPV and NPV of 93%, 64%, 81% and 82% at patient-level, and 82%, 85, 79% and 81% at lesion-level analyses. Head-to-head comparisons showed significantly higher specificity and PPV than mpMRI with absolute differences of 16% and 13% at patient-level, 6.8% and 8.5% at lesion-level analyses respectively. If patients who have negative findings on combined imaging don’t undergo biopsy, 63% of patients who don’t have csPCa can avoid unnecessary biopsies while missing only 5% of patients with csPCa. On DCA, combined imaging outperforms upfront biopsy at risk thresholds of 8% onwards which suggests that except for men with very low thresholds for missing csPCa, combined imaging can safely replace prostate biopsy. Additionally, synchronous reading of PSMA-PET/CT with mpMRI was found to be significantly more sensitive but less specific than PSMA-PET/MRI.