ROLE OF NBI IN AVOIDING UNNECESSARY BLADDER BIOPSY

Abstract

Background: Narrow Band Imaging (NBI) cystoscopy is an optical enhancement technique developed to improve mucosal and vascular visualization, allowing early and precise detection of bladder neoplasms. By filtering white light into narrow spectral bands, NBI enhances the contrast of vascular structures associated with malignancy. Despite its proven advantages in gastrointestinal endoscopy, its diagnostic value in bladder tumor detection compared with conventional White Light Cystoscopy (WLC) remains underexplored, especially in local clinical settings.

Objective: This study aimed to assess the diagnostic accuracy of NBI cystoscopy in detecting bladder tumors and to evaluate its effectiveness in reducing unnecessary biopsies compared with WLC.

Methods: A prospective observational study was conducted among 40 patients aged 18 years or older who presented with hematuria or symptoms suggestive of bladder malignancy. All patients underwent both WLC and NBI cystoscopy sequentially in the same session. Lesions were independently evaluated by two experienced urologists blinded to each other’s findings. Biopsies were performed on lesions identified as suspicious by either modality, and histopathology served as the gold standard. Diagnostic parameters, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated using SPSS version 25.

Results: NBI detected 30 suspicious lesions compared with 25 detected by WLC. Histopathology confirmed 22 lesions as malignant. NBI demonstrated superior sensitivity (93.3%) and specificity (88.9%) compared with WLC (73.3% and 66.7%, respectively). The PPV and NPV of NBI were 86.7% and 94.4%, respectively. Importantly, NBI reduced unnecessary biopsies by 87.5%, as seven of eight deferred lesions were confirmed benign upon follow-up, highlighting its role in minimizing invasive procedures.

Conclusion: NBI cystoscopy offers significantly improved diagnostic accuracy over WLC, enhancing bladder tumor detection and reducing unwarranted biopsies. These findings advocate for incorporating NBI into clinical protocols for managing non-muscle invasive bladder cancer. Future large-scale, multicenter studies are recommended to validate these results and optimize its clinical integration.