(UroToday.com) The joint session of the European Association of Urology (EAU) and the Maghreb Union Countries included a bladder cancer session and presentation by Dr. Mohamed Tetou discussing advances in optics in the visualization of non-muscle invasive bladder cancer (NMIBC).
White-light cystoscopy is the diagnostic standard for the detection of bladder cancer, however, it is often challenging secondary to the necessity of detecting small papillary and carcinoma in situ lesions. In most cases, recurrence is secondary to incomplete tumor excision during TURBT using white light cystoscopy. Thus, there is a need for an imaging modality with greater sensitivity, and there have been several adjunctive optical imaging technologies developed to improve bladder cancer detection and resection:
Blue light cystoscopy uses fluorescent enhancement by way of a photosensitizing agent in the bladder, such as ALA or HAL. These agents accumulate ~20 times more in neoplastic tissue than in healthy tissue, and under subsequent blue light illumination, neoplastic cells fluoresce red, enabling visualization of the tumor. Early data suggest that blue light cystoscopy increases tumor detection rate by 20-90%, specifically for the detection of CIS, is safe, with decreased recurrence rates (8-year recurrence-free survival 71% vs 45% for white light cystoscopy).
Narrowband imaging is produced by the filtering of a white light source into blue and green wavelength spectrums. This light is strongly absorbed by hemoglobin and has higher contrast between health mucosa and well-vascularized lesions. Narrow-band imaging has been shown to improve detection of NMIBC and CIS compared to standard white-light cystoscopy at the per patient and per lesions level, as well as decreasing recurrence rates. To date, there has been no impact on progression rate, but the technology is safe, with cost savings of ~$230-500 per patient per year.
Confocal laser endomicroscopy is high-resolution imaging in vivo and provides real-time information on living cell morphology and tissue architecture by way of fiber optic probes, fluorescein, and conventional histopathology:
Confocal laser endomicroscopy has improved sensitivity and specificity for low and high-grade bladder cancer compared to white light cystoscopy, however with the limitations that it uses a small field of view, has limited tissue penetration, and is not practical for surveying the entire bladder.
Optical c is a minimally invasive, real-time, microstructural imaging modality that uses near-infrared light for a point analysis of the bladder-wall microstructure using a probe measuring 2.7 mm in diameter. The image results are similar to those obtained by histopathology, as follows:
The main advantage is the ability of optical coherence tomography to be able to differentiate tumor staging into Ta, T1, and T2 in real-time.
Dr. Tetou concluded his presentation with the following take-home points:
- High-quality TURBT is essential in the management of bladder cancer
- Technologies are available to assist with visualization of tumors, which can improve outcomes
- Narrowband imaging leads to increased detection of lesions and reduced recurrence rates
- Fluorescence-based cystoscopy improves detection of Ta/T1 and CIS lesions, as well as decreasing recurrence risk and potentially decreasing progression risk
- These technologies are supported by the EAU and AUA
Presented by: Mohamed Tetou, HMIMV Urology Department, Rabat, Morocco
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2021 European Association of Urology, EAU 2021- Virtual Meeting, July 8-12, 2021.