Is Prolonged Systemic Immunotherapy Necessary After Achieving Tumor-free Status in Patients With Extensive Transurethrally Unresectable Very-high-risk NMIBC?

Patients with extensive transurethrally unresectable very-high-risk non-muscle-invasive bladder cancer (NMIBC) may achieve a tumor-free status after systemic immunotherapy-based bladder-sparing treatment combined with transurethral resection of bladder tumor (TURBT). However, the optimal duration of systemic immunotherapy after achieving a tumor-free status remains uncertain. Prolonged treatment may increase toxicity, treatment burden, and cost, while some patients may maintain durable disease control without continued therapy. This randomized study aims to evaluate whether active surveillance after achieving tumor-free status is a feasible alternative to continued systemic immunotherapy in patients with extensive transurethrally unresectable very-high-risk NMIBC. Patients will initially receive systemic immunotherapy-based treatment followed by disease evaluation using cystoscopy with biopsy and/or TURBT, urine cytology, urinary tumor DNA (utDNA), and imaging assessments. Patients who achieve tumor-free status after treatment and complete resection of visible disease will be randomized to either active surveillance or continued systemic immunotherapy. The study will evaluate recurrence outcomes, bladder preservation, progression, safety, and patient management strategies following achievement of tumor-free status. The trial also aims to explore the role of urinary tumor DNA in identifying patients who may safely undergo treatment de-escalation and active surveillance.