BCG不応性疾患における膀胱温存ナビゲーション：リスクはどこまで許容されるか？

Management of Bacillus Calmette-Guérin-unresponsive non-muscle-invasive bladder cancer (BCG-unresponsive NMIBC) is rapidly evolving, with an expanding range of bladder-sparing therapies challenging the traditional paradigm of early radical cystectomy. This review is timely given the growing need to balance oncologic safety with quality-of-life considerations in patients who are unfit for or unwilling to undergo cystectomy.

Recent studies have demonstrated clinically meaningful response rates with several bladder-sparing strategies, including intravesical chemotherapy combinations, gene therapy, immune-modulating agents, and systemic immunotherapy. Although durability varies and cross-trial comparisons are limited, emerging data suggest that, in carefully selected patients, an initial bladder-sparing approach followed by timely salvage cystectomy - if required - may achieve oncologic outcomes comparable to upfront cystectomy, provided progression to muscle-invasive disease is avoided.

Bladder preservation in BCG-unresponsive NMIBC should be framed as a preference-sensitive decision that integrates individual progression risk, feasibility of delayed cystectomy, and patient-valued functional outcomes. Rather than a fixed threshold, acceptable oncologic risk represents a negotiated balance, with the urologist acting as a navigator who defines safety boundaries while supporting informed, patient-centered decision-making.