Prognostic variations between “primary” and “progressive” muscle-invasive bladder cancer following radical cystectomy: A novel propensity score-based multicenter cohort study

Abstract

Objective: To assess prognostic differences between primary and progressive muscle-invasive bladder cancer (MIBC) following radical cystectomy. Material and methods: The Surveillance, Epidemiology, and End Results (SEER) database was used to abstract MIBC data following radical cystectomy from 2000-2019. Patients were classified as either ‘Primary’ MIBC (defined as the presentation of muscle-invasive disease at initial diagnosis) or ‘Progressive’ MIBC (defined as a non-muscle invasive disease that later progressed to MIBC). Baseline characteristics for the two groups were balanced using a propensity score overlap weight (PSOW) technique. Survival differences between the two groups were analyzed using Kaplan-Meier’s plots and log-rank tests. Cox’s proportional hazard regression was used to assess risk factors associated with overall survival (OS) and cancer-specific survival (CSS). Results: 6,632 MIBC patients were identified in the SEER database. Among them, 83.3% (n=5,658) were considered primary MIBC patients, and 16.7% (n=974) were categorized as progressive MIBC patients. Distribution of baseline covariates, including age, sex, race, T stage, N stage, tumor grade, marital status, and chemotherapy, were well-balanced after PSOWs were applied. After stable PSOW adjustments, Kaplan-Meier survival analysis showed that the CSS for progressive MIBC (hazard ratio [HR]=1.25, 95% confidence interval [CI]: 1.12-1.38, P<0.001) was poorer than the primary MIBC group. However, the difference in OS (HR=1.08, 95%CI: 0.99-1.18) was not significant (P=0.073). Multivariate analysis also suggested that patients with progressive MIBC have significantly poorer CSS (HR=1.24, 95%CI: 1.19-1.38, P<0.001) but not OS (HR=1.08, 95%CI: 0.99-1.18, P=0.089). Conclusion: CSS for progressive MIBC patients appears worse than for those with primary MIBC. This highlights the need to direct more resources for this patient population and particularly for high-risk cases of non-NMIBC, where timely radical surgery will improve patients prognoses.