Optimal pathological response after neoadjuvant chemotherapy for muscle-invasive bladder cancer: results from a global, multicentre collaboration

Objectives To evaluate outcomes of patients achieving a post-treatment pathological stage of <ypT2N0 at radical cystectomy (RC) following neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) to identify an optimal definition of pathological response. Patients and Methods Patients from 10 international centres who underwent NAC for cT2-4aN0-1 MIBC and achieved <ypT2N0 disease at RC were included. The primary outcome was time to recurrence, either local or distant. Kaplan-Meier and Cox proportional hazards regression were used to evaluate associations between clinicopathological variables and outcomes. Results A total of 625 patients were included. The median age was 66 years and 80% were male. Gemcitabine and cisplatin (GC, 56%) and methotrexate, vinblastine, doxorubicin and cisplatin (MVAC)/dose-dense (dd)MVAC (32%) were the most common NAC regimens. ypT0, pure ypTis, ypTa +/- ypTis and ypT1 +/- ypTis were attained in 58.1%, 20.0%, 7.6% and 14.2% of patients, respectively. The cumulative incidence of recurrence at 5 years was 9%, 16%, 29% and 30%, respectively. Pathological stage was prognostic for recurrence, with ypTa +/- Tis (hazard ratio [HR] 3.20, 95% confidence interval [CI] 1.40-7.30) and ypT1 +/- Tis disease (HR 4.03, 95% CI 2.13-7.63) associated with a significantly higher recurrence risk. Pure ypTis (HR 1.66, 95% CI 0.82-3.38) and the type of NAC regimen (ddMVAC: HR 1.59, 95% CI 0.55-4.56; MVAC: HR 1.18, 9%% CI 0.25-5.54; reference: GC) were not associated with recurrence. Conclusion We propose that optimal pathological response after NAC be defined as attainment of ypT0N0/ypTisN0 at RC. Patients with ypTaN0 or ypT1N0 disease (with or without Tis) at RC displayed a significantly higher risk of recurrence and may be candidates for trials investigating adjuvant therapy.