Non-muscle invasive micropapillary urothelial carcinoma of the bladder: Variable use of initial cystectomy versus intravesical bacillus calmette-guérin

Abstract

Introduction and Objective Micropapillary urothelial carcinoma (MPUC) is a rare and aggressive histologic variant of bladder cancer. Treatment guidelines recommend forgoing Bacillus Calmette-Guérin (BCG) therapy in favor of early radical cystectomy for non-muscle invasive (NMI)-MPUC due to high rates of disease progression. We aimed to evaluate its management in patients with immediate cystectomy and BCG across various centers. Methods Patients with MPUC were identified from the National Cancer Database (2004-2017). Treatment trends and rates of pathological upstaging were identified. Bivariate and multivariate analyses were performed to assess differences in outcomes by treatment approach. Results 1,685 patients were diagnosed with MPUC during the study period with 531 identified with localized Ta, T1, or Tis disease. BCG was administered as an initial therapy in 24.1% of NMI-MPBC patients and in 16.3% of NMI-non-MPUC patients (p<0.001). Cystectomy was performed as primary therapy for NMI disease in 29.9% of MPUC and in 2.7% of non-MPUC patients (p<0.001). Of the patients who underwent primary cystectomy, upstaging from NMI-MPUC to T2-T4 disease was seen in 46.5% of the MPUC patients compared to 37.3% in patients with non-MPUC (p=0.025). Upstaging to pathologic N1-3 disease was observed in 33.1% of MPUC patients compared to 11.9% non-MPUC patients (p<0.001). Cox regression analysis, adjusting for patient age, sex, race, comorbidities, and disease stage, care at academic cancer centers were associated with increased odds of having cystectomy as primary therapy compared to community cancer centers (OR = 4.29, 95% CI 2.73-6.76). Conclusion The current study lends evidence to current practice guidelines by reporting treatment patterns for patients with micropapillary bladder cancer across a broad spectrum of clinical practice. NMI-MPUC patients treated at academic cancer centers were more likely to receive radical surgery as primary treatment compared to patients at the community cancer centers.