Clinical feasibility of mpMRI in determining bladder-sparing strategy after initial systemic therapy for muscle-invasive bladder cancer

Motivation: NacVI-RADS based on mpMRI, was exclusively constructed to evaluate the response to systemic therapy and provided a reference for further treatment for patients with muscle-invasive bladder cancer (MIBC). Goal(s): To examine the feasibility of the nacVI-RADS criteria in driving the therapeutic decision. Approach: Patients received bladder sparing treatment were retrospectively retrieved. Pre-treatment and follow-up MRI were independently reviewed by two readers using the nacVI-RADS. We observed the pathological results from salvage RC and oncological outcomes for patients continuing systemic treatment with different nacVI-RADS category. Results: We confirmed the consistency between the nacVI-RADS score and outcomes to initial treatment both pathologically and oncologically. Impact: We preliminarily verified the feasibility of mpMRI in determining continuing or quitting bladder-sparing strategy after initial systemic therapy for MIBC. Besides, we modified nacVI-RADS, which showed a significantly improved performance in predicting the oncological outcomes after undergoing bladder sparing strategy.