The current landscape of bladder-sparing therapies in BCG-refractory high-risk nonmuscle-invasive bladder cancer

Intravesical Bacillus Calmette-Guérin (BCG) immunotherapy after transurethral resection of bladder tumor has become the first-line treatment for high-risk nonmuscle-invasive bladder cancer. However, disease recurrence or progression occurs in some patients after BCG therapy. Radical cystectomy is the standard treatment for BCG failure; however, it is not suitable for all patients and the development of alternative therapies is crucial. In addition to traditional intravesical chemotherapy (e.g., gemcitabine and docetaxel), new emerging approaches, including modified BCG, immune checkpoint inhibitors, gene therapy, and oncolytic virus therapy, have provided alternative treatment options and improved outcomes for patients.