Recent advancements in the diagnosis and treatment of non-muscle invasive bladder cancer: Evidence update of surgical concept, risk stratification, and BCG-treated disease

In the management of non-muscle invasive bladder cancer (NMIBC), disease progression and long-term control are determined by the intensity of delivered treatment and surveillance and the cancer cells' biological nature. This requires risk stratification-based postoperative management, such as intravesical instillation of chemotherapy drugs, Bacillus Calmette-Guerin (BCG), and radical cystectomy. Advancements in mechanical engineering, molecular biology, and surgical skills have evolved the clinical management of NMIBC. In this review, we describe the updated evidence and perspectives regarding the following aspects: (1) advancements in surgical concepts, techniques, and devices for transurethral resection of the bladder tumor; (2) advancements in risk stratification tools for NMIBC; and (3) advancements in treatment strategies for BCG-treated NMIBC. Repeat transurethral resection, en-bloc transurethral resection, and enhanced tumor visualization, including photodynamic diagnosis and narrow-band imaging, help reduce residual cancer cells, provide accurate diagnosis and staging, and sensitive detection, which are the first essential steps for cancer cure. Risk stratification should always be updated and improved because the treatment strategy changes over time. The BCG-treated disease concept has recently diversified to include BCG failure, resistance, refractory, unresponsiveness, exposure, and intolerance. A BCG-unresponsive disease is an extremely aggressive subset unlikely to respond to a rechallenge with BCG. Numerous ongoing clinical trials aim to develop a future bladder-sparing approach for very high-risk BCG-naive NMIBC and BCG-unresponsive NMIBC. The key to improving the quality of patient care lies in the continuous efforts to overcome the clinical limitations of bedside management.