Narrow Band Imaging (NBI) cystoscopy and assisted bipolar TURBT:
a preliminary experience in a single centre.
R.Giulianelli,B.C.Gentile, G. Mirabile, P. Tariciotti, G.Rizzo,L.Albanesi, G.Vincenti
DIVISION OF UROLOGY, NUOVA VILLA CLAUDIA
Narrow Banding Imaging (NBI) was developed with the goal of enhancing the definition of bladder's lesions that might be missed during White Light (WL) endoscopy.
The aim of this study was to evaluate, in the same patient before WL transurethral resection of bladder tumours (TURBT), the possibility to increase our ability to detect bladder cancer comparing the predictive power of lesions visible at NBI versus lesions visible at white light cystoscopy.
The secondary objective was to evaluate how the preoperative use of NBI cystoscopy can increase the ability to detect bladder lesions in terms of status, multi-focality and dimensions after TURBT, as opposed to WL cystoscopy.
Between June 2010 and April 2012, 797 consecutive patients, 423 male and 374 female, affected by suspected bladder cancer lesions, on the basis of the EAU Guideline 2010, were underwent to WL plus NBI cystoscopy and subsequently to WL Bipolar Gyrus PK (Olympus, Tokyo, Japan) TURBT. All patients underwent preoperative white light cystoscopy: topography with characterization of neoplasms and/or suspicious lesions followed by a similar evaluation using NBI. Subsequently all the patients underwent by same surgeon to WL resection (WLTURBT) of the previously identified lesions. All the removed tissue was sent separately for histological evaluation after mapping the areas of resection on a topographic sheet.
Outcomemeasurements and statisticalanalysis:
We evaluated of the accuracy of NBI compared to WL cystoscopy. Matched pairs two-tail z-test conducted to determine whether the difference between the two groups of positive results achieved by WL and by NBI is significant. The related confidence intervals have been calculated (significance level α=0,05). In order to quantify how strong is the difference, OR and RR have been built up.
In our study we considered 797 patients that matched our inclusion criteria. Through the use of WL Cystoscopy, we identified 602 patients (75.53%) with suspicious lesions, instead, with the use of light NBI, we found 786 patients (98.49%)
The use of NBI Cystoscopy increases by approximately 30% need to be specific the ability to detect lesions not otherwise visible with the only WL cystoscopy (OR 21.9 and RR 1.30), this is specific for patients with lesions size <3 cm (OR 24.00; RR 1.40), unifocal (OR: 22.28; RR 1.47) and recurrent lesions (OR 58.4; RR 1.34).
Pathology demonstrated the presence of cancer in 512 (64,2 %) patients, of whom 412 (51,8%) were visible both with WL cystoscopy and NBI cystoscopy.
In our experience, only 12 (1,5%) lesions were only positive in WL cystoscopy ( negative at NBI cystoscopy) thus 500 (62,7%, OR 10.13; RR 1.21) patients showed bladder oncological lesions positive atNBI cystoscopy. In these patients, the use the NBI Cystoscopy has highlighted a recurrence (p<0.005; OR 22.8, RR 1,23; 95% CI-1.13 to 0.24), <3 cm (p<0.05; OR 11,4 , RR 1,30; 95% CI-0.18 to 0.29) and unifocal lesions (p<0.005; OR 10,38, RR 1,34, CI 0.18 to 0.30)
The use of NBI cystoscopy, significantly increases by approximately 30% our predictive power to identify lesions not visible with WL cystoscopy, especially for unifocal lesions, those < 3 cm and recurrence lesions . Following WLTURBT, status , dimensions and focalities are statistically significants (p<0,001) to detect bladder oncological lesions following NBI cystoscopy than WL cystoscopy.