Fluorescence cystoscopy with high-resolution optical coherence tomography imaging as an adjunct reduces false-positive findings in the diagnosis of urothelial carcinoma of the bladder.

Abstract

The advantage of photodynamic diagnosis in detecting urothelial cell carcinoma (UCC) of the bladder has been demonstrated clearly, but it comes at the price of a higher false-positive rate. Optical coherence tomography (OCT) is a noninvasive, real-time, microstructural imaging modality that uses near-infrared light for a point analysis of the bladder-wall microstructure. To evaluate whether adding targeted OCT analysis of lesions that are suspicious at white-light (WL) and hexaminolevulinate (HAL) fluorescence cystoscopy improves diagnostic accuracy in the detection of UCC. In this prospective single-center study with same-patient comparison, patients with suspected UCC first received an intravesical instillation of HAL. Cystoscopy was performed in WL, followed by blue-light inspection and OCT scanning. Suspicious lesions identified by WL or HAL were evaluated by OCT and were subsequently resected or biopsied. We measured changes in sensitivity and specificity in detecting UCC using WL, HAL, and targeted OCT. In 66 patients studied, 232 lesions were detected, were scanned by OCT, and were subsequently resected or biopsied. Additionally, 132 areas of normal-appearing urothelium were investigated by all three methods and biopsied. On a per-lesion basis, sensitivity and specificity were respectively 69.3% and 83.7% for WL, 97.5% and 78.6% for HAL, and 97.5% and 97.9% for HAL combined with OCT. Overall, UCC was diagnosed in 58 patients (87.9%), with a per-patient sensitivity of 89.7% for WL and 100% for both HAL alone and HAL with targeted OCT. Per-patient specificity for HAL alone and targeted HAL was 62.5% and 87.5%, respectively. The limitation of OCT results from poor visualization of flat lesions in WL, making scanning a time-consuming procedure. Combining fluorescence cystoscopy with targeted OCT increases the specificity of fluorescence cystoscopy significantly, with no added morbidity, and reduces the need for unnecessary (false-positive) biopsies.