Urothelial Carcinoma in Bladder Diverticula: A Multicenter Analysis of Characteristics and Clinical Outcomes

Urothelial carcinoma arising in a bladder diverticulum (UCBD) is uncommon, and data on treatment and outcome are sparse.

To analyze clinicopathological characteristics of UCBD and to compare outcome after radical cystectomy (RC) and partial cystectomy (PC).

Data of 115 UCBD patients treated with RC (n=81) or PC (n=34) between 2000 and 2016 were collected from 11 institutional databases and were analyzed retrospectively. Median follow-up was 5.0yr (95% confidence interval [CI]: 4.0-6.2).

Upstaging of tumor stage at diagnostic transurethral resection (TUR) to the RC/PC specimen was investigated. Overall survival (OS) and metastasis-free survival (MFS) after RC and PC were analyzed using Kaplan-Meier estimates, and compared using the log-rank test. Intravesical recurrences after PC were reported. A multivariable Cox proportional-hazard model was used to identify factors associated with OS.

There were no statistically significant differences in clinicopathological characteristics between RC and PC groups. Fifty-five percent of patients with cTa/is/1 at diagnostic TUR had ≥pT2 tumors at RC/PC. Five-year OS and MFS were, respectively, 62% and 66% for RC and 66% and 55% for PC (p=0.9 and p=0.6). Intravesical tumor recurrence was seen in six of 34 (18%) PC patients. In multivariable analysis, positive surgical margins and extravesical disease (≥pT2) were associated with worse OS, whereas treatment modality was not (RC: reference; PC: hazard ratio 0.94, [95% CI: 0.47-1.90], p=0.9).

Upstaging of UCBD was frequent, indicating an inaccuracy in clinical staging. We found no differences in OS or MFS between PC and RC groups; therefore, PC may represent a feasible surgical alternative to RC in selected UCBD patients.

In this report, we looked at the treatment of urothelial carcinoma arising in a bladder diverticulum (UCBD). We found that bladder-sparing treatment by partial cystectomy may be an alternative to radical cystectomy in carefully selected UCBD patients.