Intraoperative margin assessment using fluorescence confocal microscopy during robot‐assisted radical prostatectomy: a first experience

OBJECTIVE: To evaluate the feasibility of adopting fluorescence confocal microscopy (FCM) for intraoperative assessment of positive surgical margins (PSMs) during robot-assisted radical prostatectomy (RARP) in a real-world clinical setting. PATIENTS AND METHODS: We conducted a prospective observational study including consecutive patients undergoing RARP between October 2023 and November 2024 in whom intraoperative margin assessment was performed using FCM (Histolog® Scanner; SamanTree Medical SA, Lausanne, Switzerland). After exclusion of initial learning-curve cases and non-interpretable scans, a per-patient analysis was performed. Prostate specimens were scanned ex vivo intraoperatively, and digital images were reviewed remotely and in real time by an experienced uropathologist blinded to final pathology. Final histopathological evaluation served as the reference standard. Diagnostic performance metrics included sensitivity, specificity, positive predictive value (PPV), negative PV (NPV), and overall accuracy, assessed both for any PSM and for clinically significant PSMs (≥3 mm). RESULTS: A total of 101 patients were included in the final analysis. The median (interquartile range) overall time from prostate extraction to intraoperative report was 13 (6-16) min. At final pathology, 17 patients (17%) had PSMs. For detection of any PSM, FCM demonstrated a sensitivity of 88.2%, specificity of 91.7%, PPV of 68.2%, and NPV of 97.5%, with an overall diagnostic accuracy of 91.1%. When restricting the analysis to clinically significant PSMs (≥3 mm), diagnostic performance improved, with sensitivity, specificity, PPV, and NPV of 93.8%, 91.8%, 68.2%, and 98.7%, respectively, and an overall accuracy of 92.1%. CONCLUSIONS: Intraoperative surgical margin assessment using FCM is feasible and demonstrates good diagnostic accuracy compared with final histopathology, with rapid turnaround times compatible with routine surgical workflows. Diagnostic performance improves when clinically relevant PSM length thresholds are applied. Larger multicentre studies and randomised trials are warranted to determine whether FCM-guided intraoperative decision-making can improve oncological and functional outcomes after RARP.