Advances in cystoscopic surveillance of superficial bladder cancer: detection of the invisible tumor

Objectives: To review recent advances in imaging modalities available for diagnosis and surveillance of superficial bladder cancer. Methods: Detailed PubMed searches were performed using the terms "fluorescence cystoscopy," "narrow-band imaging," and "optical coherence tomography" with "bladder cancer" and "urothelial carcinoma." Relevant literature was selected for analysis. We explored the clinical evidence to support the use of these technologies for the detection and surveillance of bladder cancer. Results: Fluorescence cystoscopy, narrow-band imaging, and optical coherence tomography are designed to improve the visualization of bladder cancer. These technological advancements have demonstrated an improvement in the detection of bladder cancer, including carcinoma in situ. Fluorescence cystoscopy has also been shown to decrease residual tumor rates and improve recurrence free survival. Both fluorescence cystoscopy and narrow-band imaging have a relatively high false positive rate. Optical coherence tomography can estimate bladder tumor stage without an invasive biopsy, however data is lacking in diagnostic accuracy. Conclusions: Evidence for the utility of fluorescence cystoscopy, narrow-band imaging, and optical coherence tomography has begun to compile. Fluorescence cystoscopy has the most evidence supporting its clinical applications. Low specificity currently limits these novel technologies from widespread use. More prospective studies are needed particularly of narrow band imaging, and optical coherence tomography. In addition, further research is necessary to determine the long-term impact of these technologies on recurrence, progression, and survival of bladder cancer.