Introduction:

Sarcomatoid bladder cancer is a rare variant of urothelial carcinoma and is associated with aggressive tumor behavior and poor prognosis. Recent studies have also suggested chemo-resistance to standard neoadjuvant regimens and high recurrence rates after definitive intervention, therefore conferring a challenging treatment dilemma for urologist and patients. In this study, we retrospectively evaluate our institutional database to delineate survival outcomes and prognostic characteristics of muscle invasive sarcomatoid bladder cancer after cystectomy and describe a unique pattern of rapid abdomino-pelvic cystic recurrence.

Methods:

Our institutional database at the University of Washington was queried to identify patients who underwent radical cystectomy for localized muscle invasive sarcomatoid and conventional (no variant histology present) urothelial carcinoma (UC) of the bladder from 2003 to 2018. Demographics, clinicopathologic characteristics, and treatment course were captured. Overall survival (OS) and recurrence-free survival (RFS) were calculated from time of cystectomy. T-test and chi-squared test were used for group comparison. Kaplan Meier method and life-table analysis were used for estimation OS and RFS, and Cox regression analysis (univariate and multivariate) was utilized for identification of prognostic factors related to OS. Variables significant in univariate Cox regression analysis were included in the final multivariate model. Log-rank test was used for comparison of OS and RFS between groups. A subgroup of patients with sarcomatoid histology was identified with a unique pattern of abdomino-pelvic cystic recurrence for comparison of prognostic outcomes, clinical course, as well as radiographic findings.

Results:

Thirty-two consecutive patients with sarcomatoid variant and 287 with conventional urothelial histology were identified. Sarcomatoid histology was associated with significantly higher rates of extravesical disease (pT3/4) compared to conventional UC (64% vs. 35%, p = 0.001), but similar node positive disease (24% vs. 20%, p = 0.588) and positive surgical margins (6% in both groups, p = 0.999). ypT0N0 rates following neoadjuvant chemotherapy were lower for patients with sarcomatoid histology (7% vs 33%, p = 0.067). Five-year cumulative OS was significantly inferior in the sarcomatoid group (41% vs 69%, p = 0.001), and the same was true for RFS (43% vs. 61%, p = 0.005). In multivariate Cox regression analysis for OS in the entire cohort, sarcomatoid histology was significantly associated with worse OS (HR: 3.4, 95% CI: 1.5-7.7, p = 0.003). Thirteen (41%) patients with sarcomatoid histology recurred after cystectomy, with nine (28%) developing abdominopelvic recurrence. Among these, 5 patients presented with a unique pattern of rapid abdomino-pelvic cystic recurrence, with average time to recurrence of < 5 months and median survival of 13.8 months. The diagnosis of recurrence in these cystic recurrent patients was typically delayed due to the cystic/fluid collection appearance leading to interventions for possible abscess, prior to diagnosis of recurrence confirmed on biopsy or fluid cytology. Representative imaging was selected to characterize this unique recurrence pattern of abdominopelvic cystic masses and fluid collections. Images 1 and 2 represent two separate patients that developed abdomino-pelvic recurrence after radical cystectomy.

Conclusion:

This represents the largest single institution series of patients with muscle invasive sarcomatoid bladder cancer treated with radical cystectomy. Sarcomatoid bladder cancer is associated with aggressive tumor behavior, with high rates of extravesical disease, limited response to neoadjuvant chemotherapy, and worse survival compared to conventional UC. Additionally, we identify a unique clinical pattern of rapid abdominopelvic cystic recurrence associated with very poor survival. Clinicians should have a high index of suspicion for disease recurrence in patients with sarcomatoid variant urothelial carcinoma that develop abdominopelvic fluid collections.

Funding: N/A