AUA 2017: Combination of RGB and Narrow Band Imaging for Discrimination of Non-Muscle Invasive Bladder Cancer

Boston, MA (UroToday.com) Dr. Lee and colleagues from South Korea presented their prospective, double-blinded controlled study of RGB and narrow band imaging (NBI) for the detection of non-muscle invasive bladder cancer (NMIBC) this morning at the 2017 AUA Annual meeting’s Uroradiology poster session. With recurrence rates >50% in patients with high grade NMIBC and the possibility of disease progression, studies evaluating new techniques for improving early detection of NMIBC are warranted.

In this trial, the authors assessed 102 consecutive patients with definite or suspected bladder cancer after white light imaging (WLI) and NBI cystoscopy performed by two urologists. Transurethral targeted biopsies were performed and the histologic outcomes were compared. A total of 172 biopsies for suspicious lesions (WLI+/ NBI+ n=145; WLI-/NBI+ n=27) were obtained, among which 17 of 27 lesions (63%) were identified by NBI only. The positive predictive value of NBI and WLI were 70.3% and 67.1%, respectively. On multivariate analysis, positive bladder cytology (HR 3.87, 95%CI 1.65-9.02) and gross papillary lesions (HR 6.80, 95%CI 3.03-15.26) were predictive of bladder cancer detection, however the red, green and blue components of NBI were not. A limitation of the study is the lack of a sample size calculation; thus, the study may have been underpowered to detect meaningful RGB differences for detection of NMIBC.

With improving imaging technology and new modalities for detecting NMIBC (ie. blue light cystoscopy with hexaminolevulinate) we continue to strive for early detection with the hope of decreased recurrence rates and ultimately decreased progression rates. The authors conclude in this study that NBI is simple and effective and does not require the use of dye in the bladder to detect NMIBC. Future larger scale studies assessing components of the RGB spectrum as predictors of NMIBC diagnosis are clearly needed.

Presented By: Kwang Suk Lee, Yonsei University College of Medicine, Seoul, South Korea

Co-Authors: Kyo Chul Koo, Do Kyung Kim, Jongsoo Lee, Jong Won Kim, Jae Yong Jeong, Sung Ku Kang, Byung Ha Chung

Written By:  Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre
Twitter: @zklaassen_md

at the 2017 AUA Annual Meeting - May 12 - 16, 2017 – Boston, Massachusetts, USA