IS WHICH OF FALSE POSITIVE BLADDER LESION’S INCIDENCE FOLLOWING NBI CYSTOSCOPY? PRELIMINARY EXPERIENCE IN A SINGLE CENTRE.

Objective

NBI (NARROW BAND IMAGING) cystoscopy provided a much better view of UCs than conventional WLI cystoscopy: with NBI the vasculature appears dark green or black against the almost white normal urothelium, whereas with WLI these lesions appear red on a background of pink normal urothelium. NBI cystoscopy provided a much clearer view of papillary tumours, in particular their delicate capillary architecture, than with WLI cystoscopy. NBI better defined the margins of lesions with surrounding normal-appearing mucosa.
The aim of this study was to evaluate the false positive bladder lesion’s NBI cystoscopy rate than WL false positive bladder lesion’s cystoscopy rate.

Methods and results

From June 2010 to April 2012, 797 consecutive patients, male and female, affected by primitives or recurrences or suspicious non-muscle invasive bladder tumours, underwent WL plus NBI cystoscopy and following to WL Bipolar Gyrus PK TURBT. The average follow-up was at 24 (16-38) months.
Indication of suitability for TURBt was provided on the basis of the EAU Guideline 2010. All patients provided written informed consent prior to the study. All procedures were carried out initially by performing a cystoscopy with white light. The characterization of the sites, including the number, size and appearance of the neoplasms, were recorded on a topographic bladder map. At this a cystoscopy with NBI was carried out to confirm what had been seen in the white light examination, and to report suspicious areas with NBI light. These, too, were recorded on the topographic bladder map. All endoscopic resections were performed with an Gyrus PK scalpel, bipolar generator (Olympus, Tokyo, Japan). Resection of each lesion was carried out with white light, whilst a resection of surgical margins was performed along with the bed of surgical resection using only NBI light, which was sent separately with a sequence number identifying them. All histopathological evaluations were performed by a single pathologist based on the 2004 WHO classification.
The follow-up was performed in according to the EAU Guide lines 2010. During the follow-up, all procedures were always performed by the same urologists who had performed the initial TURBT, after the initial assessment of the topographic map where they were shown the location of the tumours detected in white light or in NBI light.

Discussion

In our experience, in 797 patiens, before WL cystoscopy, we observed an overall suspicious bladder lesions detection rate of 75,65% (603 pts.). Following NBI cystoscopy we observed an overall increased suspicious bladder lesions detection rate of 37,89% (190 pts.). Overall false positive detection rate was 35,75% (285 pts.)
In the positive oncological specimens before WL TURBT group, we observed an overall suspicious bladder lesions detection rate by 64,24 % (512 pts), with an overall increased NBI suspicious bladder lesions, visible lesions only before NBI cystoscopies, detection rate by 12,42% (99 pts.) and an overall false positive rate by 11,91 % (95pts).
Overall false positive detection rate was 35,75% (285 pts.); of those overall false positives visible lesions only before NBI cystoscopies, were 11,91 % (95 pts) . Regarding to STATUS, FOCALITIES and DIMENSIONS increased false positive visible lesions only before NBI cystoscopy detection rate are showed in table 1 (Table 1)

References

Overall false positive detection rate was 35,75% (285 pts.); of those overall false positives visible lesions following NBI and WL cystoscopies were 11,91 % (95 pts) and 23,83% (190 pts) , respectively.