Urothelial carcinoma of the bladder with transmural and direct prostatic stromal invasion: does extent of stromal invasion significantly impact patient outcome?

Urothelial carcinoma of the bladder with prostatic stromal invasion is included in stage pT4a of the new 2010 American Joint Committee on Cancer/Tumor-Node-Metastasis classification. Despite being a strong indicator of poor prognosis, there have been few large studies investigating the impact of extent of prostatic stromal invasion on patient outcome. A search of the surgical pathology and expert consultation files at our institution was made for cystoprostatectomy specimens diagnosed as urothelial carcinoma with prostatic stromal invasion from 2002 to 2009. Cases were further stratified as follows: group 1--focal prostatic stromal invasion and group 2--extensive prostatic stromal invasion. Only patients who had surgery as monotherapy and those with available follow-up information were selected for this study. Thirty-five cases of urothelial carcinoma with prostatic stromal invasion and follow-up information were identified. Mean patient age was 70 years (range, 44-88 years). Of these 35 patients, 15 (43%) had focal prostatic stromal invasion and 20 (57%) had extensive prostatic stromal invasion. Angiolymphatic invasion was identified in 93% of group 1 cases and 79% of group 2 cases. Positive margins were identified in 50% of group 1 cases and 45% of group 2 cases. Incidence of nodal metastasis was 64% for group 1 and 60% for group 2. Four (27%) of 15 cases in group 1 and 6 (30%) of 20 cases in group 2 had various histologic variants identified. In group 1, there were 2 cases of urothelial carcinoma with micropapillary features and urothelial carcinoma with focal squamous differentiation. In group 2, there were 3 cases of urothelial carcinoma with focal squamous differentiation, 2 cases of urothelial carcinoma with focal sarcomatoid differentiation, and 1 case of urothelial carcinoma with focal micropapillary features. One- and 3-year overall survival for group 1 was 53% and 27%, respectively. One- and 3-year overall survival for group 2 was 47% and 12%, respectively. Mean survival was 17.4 and 16.3 months for groups 1 and 2, respectively. Overall survival curves did not show a statistically significant difference between the 2 groups from initial diagnosis (P = .889) and radical cystoprostatectomy (P = .369). Our study suggests that extent of prostatic stromal invasion by urothelial carcinoma of the bladder as an independent factor does not impact overall patient survival. Other well-known prognostic factors including positive margin status, presence of aggressive histologic variants of urothelial carcinoma, angiolymphatic invasion, and distant metastasis likely play more critical roles in predicting outcome in male patients who have urothelial carcinoma with prostatic stromal invasion.