AUA 2022: Primary Versus Secondary Muscle Invasive Bladder Cancer: Comparing the Pathologic and Oncologic Outcomes Between Both Forms of Muscle Invasive Disease When Treated with Standard of Care

( In a moderated poster presentation at the 2022 American Urologic Association Virtual Meeting held in New Orleans and virtually, Dr. Tarik Benidir presented an analysis aiming to understand the prognostic importance of primary versus secondary muscle invasive bladder cancer (MIBC). While most patients with MIBC initially present in this state (primary MIBC), a proportion of patients with progress to muscle invasive following initial diagnosis and treatment of non-muscle invasive disease (secondary MIBC). It is hypothesized that patients with secondary MIBC may exhibit decreased sensitivity to cisplatin-based chemotherapy. Thus, the authors sought to examine the response to neoadjuvant chemotherapy (NAC) and oncologic outcomes between patients with primary and secondary MIBC receiving radical cystectomy at a high-volume tertiary care center.

To do so, they performed a retrospective review of patients undergoing radical cystectomy (RC) from 2010 to 2019 who had cT2-T4/N0 disease and were treated with a cisplatin-based NAC regimen. Patients were defined as secondary MIBC if they had a history of NMBIC, were treated with at least one course of induction BCG, and progressed to MIBC. Our primary outcomes of interest were down-staging rates, which were defined as <pT2/N0, and complete pathologic response (pT0/N0). Secondary outcomes included cancer specific survival (CSS), overall survival (OS), and recurrence free survival (RFS). Categorical variables were compared with the Pearson-Chi Square test. Survival outcomes were assessed using the Kaplan-Meier method with log rank. Multivariate Cox Proportional Hazards models were utilized to identify predictors of survival outcomes.

The authors identified 333 patients who were included, of whom 48 had secondary MIBC and 285 had primary MIBC. Following NAC, there were no differences in down-staging rates at the time of radical cystectomy between those with secondary MIBC(54%) and primary MIBC (51%, p=0.67). Similarly, there were no differences in complete pathologic response rates between the (secondary: 33% vs. primary: 28%, p=0.41), CSS (p=0.97), OS (p=0.94), or RFS (p=0.83). 

On Cox Proportional Hazards regression, only >pT2 and N+ disease predicted poorer CSS, OS, and RFS.

Dr. Benidir, therefore, concluded that, while secondary MIBC is relatively uncommon, in this population receiving guideline concordant treatment, there were no differences in pathologic response or survival outcomes.

Presented by: Tarik Benidir, MD, FRCS, MSc, Resident, Cleveland Clinic, Cleveland, Ohio

Written by: Christopher J.D. Wallis, University of Toronto Twitter: @WallisCJD during the 2022 American Urological Association (AUA) Annual Meeting, New Orleans, LA, Fri, May 13 – Mon, May 16, 2022.

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