Prognostic significance of bladder neck involvement in non-muscle-invasive bladder cancer: A SEER database analysis with 19,919 patients

PURPOSE To study prognostic values of bladder neck involvement (BNI) and survival outcomes in non-muscle-invasive bladder cancer (NMIBC). METHOD AND MATERIALS The national Surveillance, Epidemiology, and End Results database (2004-2015) was applied to gain further insight into the prognostic values of BNI and 19,919 patients diagnosed with NMIBC were included in our study. We used the Kaplan-Meier method with the log-rank test and subgroup analyses to evaluate cancer-specific survival (CSS) and overall survival (OS). In addition, the multivariable Cox proportional hazard model and propensity score matching (PSM) were utilized. RESULTS In all, 3446 patients with BNI and 16,473 patients with sites except for bladder neck were enrolled in our study. Compared with other sites, a tendency toward a higher proportion of higher grade (p   0.05). In addition, subgroups stratified by tumor size and grade all revealed poor prognosis of BNI in NMIBC patients. Moreover, better survival outcomes of OS were observed in BNI patients who received radical cystectomy (p = 0.02) or chemotherapy (p < 0.001) multivariable Cox regression after PSM revealed that the BNI group had a higher risk of overall mortality (OM) (BNI vs. other sites hazards ratios [HR]: 1.127, 95% CI: 1.154-1.437, p < 0.001) and cancer-specific mortality (CSM) (BNI vs. other sites HR: 1.127, 95% CI: 1.039-1.223, p < 0.001), while before PSM, similar situations were only existed in CSM (BNI vs. other sites HR: 1.288, 95% CI: 1.154-1.437, p < 0.001). CONCLUSIONS The prognosis of BNI was poorer than that of the other sites. BNI was an independent risk factor for OM and CSM in patients with NMIBC, especially for those with Ta or T1 stage.