Delphi consensus on ex vivo fluorescence confocal microscopy in robot-assisted radical prostatectomy

Positive surgical margins (PSMs) after robot-assisted radical prostatectomy (RARP) increase the risk of prostate cancer recurrence, often requiring salvage treatments that may compromise functional recovery. Intraoperative frozen section can detect PSM but is not feasible as a routine approach in most settings. Ex vivo fluorescence confocal microscopy (FCM) provides a rapid, real-time alternative, though evidence remains limited and knowledge gaps persist. This international Delphi consensus aimed to define expert recommendations on the clinical application of and workflow and research priorities for the safe integration of FCM during RARP.

A modified Delphi process was conducted following the RAND/UCLA Appropriateness Method and reported according to the ACCORD checklist. In total, 32 international experts in urology and pathology participated in a hybrid consensus meeting after structured literature review and preparatory online sessions. Forty-four evidence-based multiple-choice items across patient selection, image acquisition, and surgical management domains were developed and anonymously voted on via a secure online platform. Consensus was predefined as ≥80% agreement among respondents.

Consensus was achieved for 24 of 44 items (55%). Key agreements included a risk-adapted use of FCM (97%), its role as an adjunct to magnetic resonance imaging for nerve-sparing decisions (87%), adoption of en-face imaging as the preferred FCM technique (82%), and a maximum reporting time of 30 min (85%). The panel endorsed formal certification for image interpretation (83%), standardized reporting of positive margin length (82%), and feasibility of remote intra-institutional reporting (84%). Larger (>3 mm) PSM in high-risk cases warranted complete neurovascular bundle resection (96%).

This consensus provides a structured framework for the intraoperative use of FCM during RARP, defining its indications, workflow standards, and training requirements. Future multicentre studies are needed to assess its oncological and functional impact and to establish standardized implementation pathways.