Endoscopic Molecular Imaging plus Photoimmunotherapy: A New Strategy for Monitoring and Treatment of Bladder Cancer

Due to the high recurrence and progression rate of non-muscle invasive bladder cancer after transurethral resection of bladder tumor, some new optical imaging technologies have arisen as auxiliary imaging modes for white light cystoscopy to improve the detection rate of small or occult tumor lesions, such as photodynamic diagnosis, narrow-band imaging, and molecular imaging. White light cystoscopy is inadequate and imperfect for bladder cancer detection, and thus residual tumors or coexisting flat malignant lesions, especially carcinoma in situ, would be ignored during conventional resection. The bladder, a hollow organ with high compliance, provides an ideal closed operation darkroom for endoscopic molecular imaging free from interference of external light sources. Also, intravesical instillation of a molecular fluorescent tracer is simple and convenient before surgery through the urethra. Molecular fluorescent tracer has high sensitivity and specificity to tumor cells, and its mediated molecular imaging allows small or occult tumor lesion detection while minimizing false-positive results. Meanwhile, endoscopic molecular imaging provides a real-time and dynamic image during surgery, which helps urologists to perform high-quality and complete tumor resection through accurate judgment of tumor boundaries and depth of invasion. Photoimmunotherapy is a novel molecular targeted therapeutic pattern of photodynamic therapy that kills malignant cells selectively and minimizes the cytotoxicity to normal tissues. The combination of endoscopic molecular imaging and photoimmunotherapy used in initial treatment may avoid the need of repeat transurethral resection in strictly selected patients and improve oncological outcomes such as recurrence-free survival and overall survival after operation.