BERKELEY, CA (UroToday.com) - Upper urinary tract transitional-cell carcinoma (UUT-TCC) diagnosis continues to represent a significant challenge in the urologic field.
While allowing the urologist to perform visual inspection of the entire renal collecting system, flexible ureteroscopy emerged as a promising alternative.
In this regard, digital flexible ureteroscopy (DFU) in general and the new Olympus URF-V device (Olympus Surgical, Orangeburg, NY) in particular seem to provide large size, high-resolution images, thus enabling a close and detailed observation of upper tract lesions. This new device adds the advantages related to narrow-band imaging (NBI), a technology which filters white light (WL) into two narrow-bands (415 and 540 nm), strongly absorbed by hemoglobin, thus penetrating the tissue surface and increasing the visibility of surface capillaries (shown in brown) and blood vessels (veins displayed in cyan) in the submucosa. Also, the URF-V ureteroscope offers the largest image size currently available, about 3 times larger than that of conventional fibroscopes.
Due to the vascular nature of urothelial carcinoma, NBI was determined to enhance the contrast between superficial tumors and the normal urothelial mucosa. An abnormal appearance under NBI mode was considered as any area discordant in appearance with the WL image by either blood vessels’ concentration or general aspect.
The present trial aimed to determine if NBI could actually improve the detection of UUT-TCC lesions by comparison to WL alone while performing DFU. A total of 27 patients were included in the study, of which 14 were previously diagnosed and treated conservatively for UUT-TCC and 13 were admitted for first suspicion of upper tract malignancy based on hematuria, positive cytology, IVP or CT.
The procedure consisted of a careful examination of the renal collecting system using the URF-V DFU in WL mode, resulting in a map of the suspicious lesions, followed by NBI, which described a specific map of all distinctive lesions. Biopsies were taken (by Piranha biopsy forceps) from all the detected lesions, followed by holmium laser vaporization and NBI control of the lesion margins. The specimens were interpreted by a dedicated pathologist, blinded to all clinical information except the anatomic location of the specimen.
In total, there were 35 pathologically confirmed UUT-TCC tumors, of which NBI exclusively diagnosed 5 additional tumors (14.2%) and identified the extended limits for another 3 tumors (8.5%). Consequently, the overall tumor detection rate was improved by 22.7% due to the use of NBI.
Subjectively speaking, the NBI mode emphasized the specific vascular architecture of UUT-TCC, thus creating the impression of a three dimensional visualization of the tumors and, at the same time, clearly defining their limits. The spatial representation of tumors, based on their vascular structure, improved the diagnostic accuracy of the method.
In conclusion, NBI appears to represent a valuable diagnostic technology for UUT-TCC, showing considerable improvement in terms of tumor visualization accuracy as well as detection rate. It also enables the urologist to determine the exact limits of tumors, subsequently facilitating complete laser vaporization. Of course, further studies will be needed in order to clarify the impact of this procedure on the diagnosis, recurrence rate, tumor-free survival period and overall evolution of these patients.
Written by:
Olivier Traxer, MD and Bogdan Geavlete, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
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