Intraoperative evaluation of detrusor muscle during transurethral resection of bladder tumour using confocal fluorescent microscopy

OBJECTIVES: To evaluate the feasibility of confocal fluorescence microscopy (CFM) for identifying detrusor muscle presence during transurethral resection of bladder tumour (TURBT). PATIENTS AND METHODS: A total of 36 specimens from 17 patients were prospectively collected. The resected surfaces were analysed intraoperatively using CFM to evaluate the presence of detrusor muscle. All CFM images were independently reviewed by two board-certified genitourinary pathologists and two urology trainees, who have completed the necessary CFM training. Interobserver agreement was assessed, and diagnostic concordance between the CFM interpretations, standard cystoscopic evaluation, and final haematoxylin and eosin analysis, were analysed. RESULTS: All specimen preparations and CFM scanning were completed within 5 min. Interobserver agreement between the two pathology reviewers was 91.7%. When compared with final histopathology, expert pathology readers achieved strong diagnostic performance using CFM, with a sensitivity of 87.5%, specificity of 90%, positive predictive value (PPV) of 87.5%, and negative PV(NPV) of 90%. By comparison, the urology trainees yielded a sensitivity of 61.9%, specificity of 100%, PPV of 100%, and NPV of 66.7%, while standard cystoscopic assessment demonstrated a sensitivity, specificity, PPV, and NPV of 100%, 50%, 71.4%, and 100%, respectively. CONCLUSION: Confocal fluorescence microscopy represents a feasible and promising adjunct for real-time intraoperative assessment of TURBT specimen adequacy and resection quality. Although expert pathology readers demonstrated superior diagnostic performance, acceptable accuracy can also be achieved by urology trainees with necessary training and additional experience. Nevertheless, larger, multi-institutional studies remain required to validate these findings and to further define the safe implementation of CFM in contemporary diagnosis and surgical management of bladder cancer.