Atlas of Ex Vivo Prostate Tissue and Cancer Images Using Confocal Laser Endomicroscopy: A Project for Intraoperative Positive Surgical Margin Detection During Radical Prostatectomy

Background: Confocal laser endomicroscopy (CLE) is an optical device that aims to image histological architecture and may be used to reduce positive surgical margins. The ability of CLE to describe prostatic and periprostatic tissues, and prostate cancer (PCa) is still an object of investigation. Objective: To create an atlas of ex vivo CLE images of prostatic and periprostatic tissues, and PCa in order to recognise different prostatic structures. Design, setting, and participants: From November 2017 to February 2018, 15 patients underwent radical prostatectomy for biopsy-proven PCa. Outcome measurements and statistical analysis: Based on preoperative data and macroscopic examination, tumour location was assessed and confirmed on frozen sections. Prior to ex vivo CLE analysis, prostates were stained with fluorescein 10%. We used a GastroFlex probe to collect images of periprostatic tissue (adipose tissue, fibrous and connective tissues, vessels, nerve sheets, seminal vesicles, and urethra). Normal prostatic glands and tumour tissue according to the Gleason grade were analysed. Each PCa Gleason score was represented. Results and limitations: A total of 139 video clips and 237 pictures of prostatic and periprostatic tissues were collected. Among them, we selected 16 highly representative images. Adipose tissue, fibrous tissue, and connective tissue were supposable in all 15 specimens. PCa glands captured fluorescein in their cytoplasm, normal prostatic glands did not capture fluorescein, and glandular structures were easily recognisable. The principal limitation of this study is its ex vivo nature of the study. Conclusions: Each CLE image was correlated with the corresponding haematoxylin/eosin/saffron definitive pathology image, allowing building of an atlas as a necessary tool to assess the diagnostic performance of CLE during radical prostatectomy in achieving negative surgical margins. Patient summary: In this study, we aim to provide an atlas of images illustrating prostatic, periprostatic, and PCa tissues obtained using Cellvizio confocal laser endomicroscopy as a tool for further interpretation of intraoperative surgical margins during radical prostatectomy.