Preliminary results and experiences of fluorescence confocal microscopy using the Histolog® Scanner in prostate cancer diagnostics: a feasibility study

OBJECTIVE: To present preliminary results and clinical experiences regarding the use of the Histolog® Scanner (SamanTree Medical SA, Lausanne, Switzerland), a fluorescence confocal microscopy (FCM)-based digital imaging device for real-time evaluation of prostate biopsy cores, and to assess its diagnostic performance compared with conventional histopathology for detecting or ruling out clinically significant prostate cancer (csPCa). PATIENTS AND METHODS: This retrospective study included 20 patients and analysed 50 prostate biopsy cores. Each selected core was examined using the Histolog Scanner and subsequently evaluated by standard histopathological processing, including haematoxylin and eosin staining and p504s/basal cell cocktail dual immunohistochemistry when indicated. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy were calculated. Our definition for csPCa was Gleason Score 3 + 4/International Society of Urological Pathology (ISUP) Grade Group ≥2 RESULTS: All biopsy cores were successfully analysed by the FCM-based technique, and the standard histopathological examination. The test results were available within 10-15 min on each occasion. Among 20 Histolog-negative samples, 18 were truly negative (NPV 90%). Of 30 Histolog-positive samples, 19 were confirmed positive, while 11 were false positives (PPV 63.3%). Sensitivity reached 90.5%, and specificity was 62.1%. Overall diagnostic accuracy was 74%. Technical challenges included occasional core drying and the learning curve required to differentiate benign lesions from low-grade malignancies. CONCLUSION: The Histolog Scanner shows promise as a rapid tool for the preliminary assessment of prostate biopsy cores, showing high NPV and sensitivity; however, the PPV and specificity turned out to be relatively low. Tissue integrity is preserved for subsequent histopathology. The limitations of our study highlight the need for larger prospective studies to refine its clinical role and determine optimal integration into PCa diagnostic workflows.