Comparative analysis of the effect of prostatic invasion patterns on cancer-specific mortality after radical cystectomy in pT4a urothelial carcinoma of the bladder

PURPOSE: To evaluate the prognostic relevance of different prostatic invasion patterns in pT4a urothelial carcinoma of the bladder (UCB) after radical cystectomy.

MATERIALS AND METHODS: Our study comprised a total of 358 men with pT4a UCB. Patients were divided in 2 groups-group A with stromal infiltration of the prostate via the prostatic urethra with additional muscle-invasive UCB (n = 121, 33.8%) and group B with continuous infiltration of the prostate through the entire bladder wall (n = 237, 66.2%). The effect of age, tumor grade, carcinoma in situ, lymphovascular invasion, soft tissue surgical margin, lymph node metastases, administration of adjuvant chemotherapy, and prostatic invasion patterns on cancer-specific mortality (CSM) was evaluated using competing-risk regression analysis. Decision curve analysis was used to evaluate the net benefit of including the variable invasion pattern within our model.

RESULTS: The estimated 5-year CSM-rates for group A and B were 50.1% and 66.0%, respectively. In multivariable competing-risk analysis, lymph node metastases (hazard ratio [HR] = 1.73, P<0.001), lymphovascular invasion (HR = 1.62, P = 0.0023), soft tissue surgical margin (HR = 1.49, P = 0.026), absence of adjuvant chemotherapy (HR = 2.11, P<0.001), and tumor infiltration of the prostate by continuous infiltration of the entire bladder wall (HR = 1.37, P = 0.044) were significantly associated with a higher risk for CSM. Decision curve analysis showed a net benefit of our model including the variable invasion pattern.

CONCLUSIONS: Continuous infiltration of the prostate through the entire bladder wall showed an adverse effect on CSM. Besides including these patients into clinical trials for an adjuvant therapy, we recommend including prostatic invasion patterns in predictive models in pT4a UCB in men.