Using photodynamic diagnosis and narrow band imaging for diagnosing and treating non-muscle-invasive bladder cancer
Abstract
Photodynamic diagnosis (PDD) and narrow band imaging (NBI) represent technologies which are complementary to standard white light cystoscopy and transurethral resection of the bladder (TURB) for the diagnostics of non-muscle-invasive bladder cancer. With improved sensitivity they facilitate endoscopy and enable a more precise diagnosis to be made.
PDD endoscopy uses an intravesical instillation of a photosensitiser and subsequent visualization of its activity using "blue" light. PDD significantly increases the detection rate of bladder tumors, especially high-grade lesions.
Several studies documented a significant improvement in diagnosis as evident from a reduction in rate of and time to recurrence. Its universal use has been limited by high cost and the fact that the procedure is more involved for patients and hospital staff.
NBI on the other hand is cheap and easy to use. The technology is based on two short wave length light beams generated with the use of a light filter.
Compared to white light, NBI significantly improves detection rates of small bladder lesions, including small recurrences. Moreover, it better defines tumor margins.
Large, randomized, prospective trials to determine the value of NBI are currently ongoing. Trials comparing the ability of NBI and PDD to reduce recurrence rates would be of great value.