Fluorescence confocal microscopy (FCM) is a new imaging modality capable of generating digital microscopic resolution scans of fresh surgical specimens, and holds potential as an alternative to frozen section (FS) analysis for intra-operative assessment of surgical margins. Previously, we described the LaserSAFE technique as an application of FCM for margin assessment in robot-assisted radical prostatectomy (RARP) using the Histolog® scanner. This study describes the accuracy and inter-rater agreement of FCM imaging compared to corresponding paraffin-embedded analysis (PA) among four blinded pathologists for the presence of positive surgical margins (PSM).
RARP specimens from patients enrolled in the control arm of the NeuroSAFE PROOF study (NCT03317990) were analysed from April 2022 to February 2023. Prostate specimens were imaged using the Histolog® scanner before formalin fixation and PA. Four trained assessors, blinded to PA, reviewed and analysed FCM images of the posterolateral prostatic surface.
A total of 31 prostate specimens were included in the study. PA per lateral side of the prostate identified 11 instances of positive margins. Among the four histopathologists included in our study, FCM achieved a sensitivity of 73-91 and specificity of 94-100% for the presence of PSM. Fleiss' Kappa for inter-rater agreement on PSM was 0.78 (95% confidence interval = 0.64-0.92), indicating substantial agreement.
This blinded analysis of FCM versus PA among histopathologists with different experience levels demonstrated high accuracy and substantial inter-rater agreement for diagnosing PSM. This supports the role of the FCM as an alternative to FS.
Histopathology. 2024 Oct 15 [Epub ahead of print]
Ricardo Almeida-Magana, Matthew Au, Tarek Al-Hammouri, Manju Mathew, Kate Dinneen, Larissa S T Mendes, Eoin Dinneen, Willem Vreuls, Greg Shaw, Alex Freeman, Aiman Haider
Department of Targeted Intervention, University College, London, UK., Department of Urology, University College London Hospitals NHS Foundation Trust, London, UK., Centre for Medical Imaging, University College, London, UK., Department of Histopathology, University College London Hospitals NHS Foundation Trust, London, UK., Department of Histopathology, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands.