Initial experience of combined use of photodynamic diagnosis and narrow band imaging for detection of flat urothelial lesion.

Background: This preliminary study is the first report to compare photodynamic diagnosis (PDD) with narrow band imaging (NBI) in the same patients with flat urothelial lesions suspicious of carcinoma in situ (CIS) of the bladder.

Methods: Between November 26, 2012 and April 1, 2013, 10 patients underwent transurethral resection of bladder tumor using PDD and NBI simultaneously because of suspicion of CIS. The bladder was mapped first under white light (WL), then under NBI, and subsequently under blue light in odd-numbered patients. The bladder was mapped first under WL, then under blue light, and subsequently under NBI in even-numbered patients. Biopsies were carried out from all suspicious areas, noting whether NBI, PDD or both detected lesions. Random cold cup biopsies from healthy mucosa of bladder were performed from lesions negative on PDD and NBI.

Results: The sensitivity and specificity of PDD for detection of CIS and dysplasia were 0.916 and 0.827, respectively. The sensitivity and specificity of NBI for detection of CIS and dysplasia were 0.625 and 0.879. The area under the curve (AUC) for detection of CIS and dysplasia was 0.872 with PDD and 0.752 with NBI. The AUC with combined use of PDD and NBI was 0.918. There was no cancer or dysplasia identified in 43 lesions that were both PDD- and NBI-negative.

Conclusion: When both PDD and NBI are negative, the possibility of CIS or dysplasia might be very low. The usefulness of the combination of PDD with NBI was suggested in this study.