BACKGROUND: Bladder cancer (UCB) staged pT4a show heterogeneous outcome after radical cystectomy (RC). No risk model has been established to date. Despite gender-specific differences, no comparative studies exist for this tumor stage. MATERIALS AND METHODS: Cancer-specific survival (CSS) of 245 UCB patients without neoadjuvant chemotherapy staged pT4a, pN0-2, M0 after RC were analyzed in a retrospective multi-center study. Seventeen patients were excluded from further analysis due to carcinoma in situ (CIS) of the prostatic urethra and/or positive surgical margins. Average follow-up period was 30 months (IQR: 14-45). The influence of different clinical and histopathologic variables on CSS was determined through uni- and multivariate Cox regression analyses. Two risk groups were generated using factors with independent effect in multivariate models. Internal validity of the prediction model was evaluated by bootstrapping. RESULTS: Eighty-four percent of the patients (n = 192) were male; 72% (n = 165) showed lymphovascular invasion (LVI). The 5-year CSS rate was 31%, and significantly different between male and female (35% vs. 15%, P = 0.003). Multivariate Cox regression modeling, female gender (HR = 1.83, P = 0.008), LVI (HR = 1.92, P = 0.005), and absence of adjuvant chemotherapy (HR = 0.61, P = 0.020) significantly worsened CSS. Two risk groups were generated using these 3 criteria, which differed significantly between each other in CSS (5-year-CSS: 46% vs. 12%, P < 0.001). The c-index value of the risk model was 0.61 (95% CI: 0.53-0.68, P < 0.001). CONCLUSIONS: Prognosis in UCB staged pT4a is heterogeneous. Female gender and LVI are adverse factors. Adjuvant chemotherapy seems to improve outcome. The present analysis establishes the first risk model for this demanding tumor stage.