Plasmacytoid variant urothelial bladder cancer: is it time to update the treatment paradigm?

Abstract

Objectives: Plasmacytoid variant (PCV) urothelial cancer (UC) of the bladder is rare, with poor clinical outcomes. We sought to identify factors that may better inform expectations of tumor behavior and improve management options in patients with PCV UC.

Materials and methods: A retrospective analysis of the Indiana University Bladder Cancer Database between January 2008 and June 2013 was performed comparing 30 patients with PCV UC at cystectomy to 278 patients with nonvariant (NV) UC at cystectomy who underwent surgery for muscle-invasive disease. Multivariable logistic regression was used to assess precystectomy variables associated with non-organ-confined disease at cystectomy and Cox regression analysis to assess variables associated with mortality.

Results: Patients with PCV UC who were diagnosed with a higher stage at cystectomy (73% pT3-4 vs. 40%, P = 0.001) were more likely to have lymph node involvement (70% vs. 25%, P<0.001), and positive surgical margins were found in 40% of patients with PCV UC vs. 10% of patients with NV UC (P<0.001). Median overall survival and disease-specific survival were 19 and 22 months for PCV, respectively. Median overall survival and disease-specific survival had not been reached for NV at 68 months (P<0.001). Presence of PCV UC on transurethral resection of bladder tumor was associated with non-organ-confined disease (odds ratio = 4.02; 95% CI: 1.06-15.22; P = 0.040), and PCV at cystectomy was associated with increased adjusted risk of mortality (hazard ratio = 2.1; 95% CI: 1.2-3.8; P = 0.016).

Conclusions: PCV is an aggressive UC variant, predicting non-organ-confined disease and poor survival. Differentiating between non-muscle- and muscle-invasive disease in patients with PCV UC seems less important than the aggressive nature of this disease. Instead, any evidence of PCV on transurethral resection of bladder tumor may warrant aggressive therapy.

Keywords: Bladder cancer; Cystectomy; Plasmacytoid variant; Variant histology.