SPARC: The Standardised Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography Analysis and Reporting Consensus: A Delphi Analysis.

[BACKGROUND AND OBJECTIVE] Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is an evolving diagnostic tool for prostate cancer. There is a need to harmonise existing guidelines and reporting recommendations for PSMA PET/CT. The Standardised PSMA PET/CT Analysis and Reporting Consensus (SPARC) project aims to consolidate classifications and recommendations by a multidisciplinary and international group of experts under one cohesive framework, establishing a dynamic and evolving structure for PSMA PET/CT reporting.

[METHODS] We employed a cross-sectional iterative process to define opinions and evaluate consensus. Thirty expert panel members, representing diverse specialities and geographic areas, were selected. A methods expert led the design, data collection, and analysis. Five groups of international multidisciplinary prostate cancer experts convened for literature review and formulation of statements on standardised reporting, detection, primary staging, biochemical recurrence, and treatment response. The groups compiled 91 statements for a two-round modified Delphi survey. The "RAND appropriateness method" was used for the analysis.

[KEY FINDINGS AND LIMITATIONS] Consensus increased to 93% between two rounds. The panel endorsed and adopted the following frameworks for reporting of PSMA PET/CT: molecular imaging PSMA for expression level and certainty, miTNM by PROMISE for reporting of PSMA PET/CT, the PRIMARY score for intraprostatic staging, PSMA volume, mean standardised uptake value, and maximum standardised uptake value (SUV). There were uncertainty about correlating PSMA PET/CT with conventional imaging risk groups in newly diagnosed metastatic prostate cancer and a lack of agreement that clinical management plans based upon PSMA PET/CT improved outcomes. There was consensus that SUVmax should be reported regionally, rather than reporting a single site. There were insufficient data to standardise a definition of response or progression by PSMA PET/CT.

[CONCLUSIONS AND CLINICAL IMPLICATIONS] SPARC provides a standardised PSMA PET/CT analysis and reporting consensus to serve as a future reference for PSMA PET/CT reporting. Integration of common PSMA PET reporting criteria under one umbrella improves the explanation of imaging findings between imaging experts and treating clinicians for clinical implementation.