Intermediate- and high-risk nonmuscle invasive bladder cancer: Where do we stand?

Abstract

Introduction: The standard of care for intermediate- and high-risk non-muscle invasive bladder cancer (NMIBC) patients is transurethral resection of bladder tumor followed by intravesical adjuvant immunotherapy with Bacillus Calmette-Guerin (BCG). However, a non-negligible portion of patients is doomed to fail BCG-therapy and, consequently, undergo radical cystectomy as only treatment option available. In this context, effective options to improve tumor response, thus delaying or even avoiding radical cystectomy, are urgently needed. A narrative review of the literature was performed to summarize the rationale and the clinical outcomes regarding the use of immunotherapy and novel therapeutic perspectives both for BCG-treated and BCG-naïve NMIBC patients.

Results: Several clinical trials are currently investigating immune checkpoint inhibitors and novel targeted approaches, including cancer vaccines, for NMIBC patients with BCG-naïve and BCG-unresponsive disease. Despite the lack of long-term safety data, novel therapeutic options, both by systemic and intravesical delivery, demonstrated a good tolerability, antitumor efficacy, and low rates of recurrence and/or progression to muscle-invasive disease.

Conclusions: Although clinical data available are mostly limited to phase I/II trials, novel targeted therapies have raised as an effective and reliable approach for patients failing BCG and for those who are therapy naïve. Phase III trials will be crucial in order to change the current clinical practice, after many years in which BCG was the only therapy available for intermediate- and high-risk NMIBC patients.

Keywords: BCG; BCG-naïve; BCG-unresponsive; Cancer vaccine; Immunotherapy; Non-muscle invasive bladder cancer.