Survival Outcomes After Immediate Radical Cystectomy Versus Conservative Management with Bacillus Calmette-Guérin Among T1 High-grade Micropapillary Bladder Cancer Patients: Results from a Multicentre Collaboration

Abstract

BackgroundLiterature lacks clear evidence regarding the optimal treatment for non–muscle-invasive micropapillary bladder cancer (MPBC) due to its rarity and the presence of only small sample size and single-centre studies. ObjectiveTo assess cancer-specific mortality (CSM) and overall mortality (OM) between immediate radical cystectomy (RC) and conservative management among T1 high-grade (HG) MPBC. Design, setting, and participantsWe retrospectively analysed a multicentre dataset including 119 T1 HG MPBC patients treated between 2005 and 2019 at 15 tertiary referral centres. The median follow-up time was 35 mo (interquartile range: 19–64). InterventionPatients underwent immediate RC versus conservative management with bacillus Calmette-Guérin. Outcomes measurements and statistical analysisCumulative incidence functions and Kaplan-Meier methods were applied to estimate survival outcomes. Multivariable Cox analyses were performed to assess independent predictors of disease recurrence and disease progression after conservative management; covariates consisted of pure MPBC, concomitant lymphovascular invasion (LVI), and carcinoma in situ at initial diagnosis. Results and limitationsImmediate RC and conservative management were performed in 27% and 73% of patients, respectively. CSM and OM did not differ significantly among patient treated with immediate RC versus conservative management (Pepe-Mori test p = 0.5 and log-rank test p = 0.9, respectively). Overall, 66.7% and 34.5% of patients experienced disease recurrence and disease progression after conservative management, respectively. At multivariable Cox analyses, concomitant LVI was an independent predictor of disease recurrence (p = 0.01) and progression (p = 0.03), while pure MPBC was independently associated with disease progression (p = 0.03). The absence of a centralised re-review and the retrospective design represent the main limitations of our study. ConclusionsConservative management could achieve satisfactory results among T1 HG MPBC patients with neither pure MPBC nor LVI at initial diagnosis. Patient summaryBacillus Calmette-Guérin seems to be an effective therapy for T1 micropapillary bladder cancer patients with neither pure micropapillary disease nor lymphovascular invasion at initial diagnosis.