Plasmacytoid variant urothelial carcinoma of the bladder: A systematic review and meta-analysis of clinicopathological features and survival outcomes

Purpose:The clinicopathological features and treatment outcomes of plasmacytoid variant-urothelial carcinoma of the bladder have not been fully understood. We evaluated the clinicopathological characteristics and survival outcomes of plasmacytoid variant-urothelial carcinoma of the bladder compared to conventional urothelial carcinoma of the bladder.Materials and Methods:A systematic review was performed following the PRISMA guideline. PubMed®/MEDLINE®, Embase® and Cochrane Library were searched up to June 2019. The differences in the clinicopathological features (stage pT3 or greater, lymph node metastasis, ureteral margin positive and perivesical soft tissue margin positive status) and survival outcomes (overall mortality and cancer specific mortality) between plasmacytoid variant-urothelial carcinoma of the bladder and conventional urothelial carcinoma of the bladder were compared. The GRADE approach was used for rating the certainty of evidence.Results:Eight studies were included. Patients with plasmacytoid variant-urothelial carcinoma of the bladder had a higher frequency of stage pT3 or greater (OR 3.84, 95% CI 1.63-9.03, p=0.002) and risk of lymph node metastasis (OR 2.58, 95% CI 1.15-5.76, p=0.02), ureteral margin positive (OR 12.18, 95% CI 4.62-32.13, p <0.00001) and perivesical soft tissue margin positive (OR 12.31, 95% CI 5.15-29.41, p <0.00001) status after radical cystectomy than those with conventional urothelial carcinoma of the bladder. Although there was no difference in cancer specific mortality (HR 1.40, 95% CI 0.82-2.40, p=0.22) between plasmacytoid variant-urothelial carcinoma of the bladder and conventional urothelial carcinoma of the bladder, plasmacytoid variant-urothelial carcinoma of the bladder had worse survival outcomes (overall mortality) than conventional urothelial carcinoma of the bladder approaching the borderline of significance (HR 1.62, 95% CI 0.98-2.68, p=0.06) when adjusted for other clinicopathological characteristics.Conclusions:Plasmacytoid variant-urothelial carcinoma of the bladder was strongly associated with adverse clinicopathological features and worse overall mortality compared to conventional urothelial carcinoma of the bladder after adjusting for other clinicopathological parameters, and plasmacytoid variant histology of urothelial carcinoma of the bladder is an independent prognostic factor for overall survival.