Photodynamic diagnosis (PDD) and narrow band imaging (NBI) are two different modalities used to improve detection of tumors, carcinoma in situ (CIS) and flat dysplasia compared to white light (WL) cystoscopy.

OBJECTIVES: To compare findings in NBI to findings in WL and PDD in a high risk patient population.

DESIGN, SETTING, AND PARTICIPANTS: 171 patients were included in the study from four different urological departments in Denmark and Norway. Patients were scheduled for a PDD-guided transurethral tumor resection or cystoscopy guided biopsy in accordance with Danish guidelines, on the suspicion of primary or concomitant CIS.

INTERVENTION: All patients were examined with WL cystoscopy followed by both NBI and PDD before biopsy.

RESULTS: A total of 136 patients were biopsied due to findings with suspicion of CIS in at least one modality (482 biopsies/3.5 biopsies per patient). Analysis at patient level showed that NBI and PDD had a significantly higher sensitivity regarding identification of CIS and dysplasia compared to WL (NBI: 95.7%, PDD: 95.7% vs. WL: 65.2%, p < 0.05). Specificity was not significantly different between the three methods (NBI: 52.0%, PDD: 48.0% and WL: 56.8%). When analyzed per biopsy, NBI and PDD had a significantly higher sensitivity than WL (NBI: 72.7% and PDD: 78.2% vs. WL: 52.7%, p < 0.05) whereas the positive predictive values were not significantly different (NBI: 23.7%, PDD: 22.2% and WL: 19.0%).

CONCLUSION: NBI was found to be a valid alternative to PDD regarding diagnosis of CIS and flat dysplasia.