The Impact of Primary Versus Secondary Muscle-invasive Bladder Cancer at Diagnosis on the Response to Neoadjuvant Chemotherapy

Background: There might be differential sensitivity to neoadjuvant chemotherapy (NAC) in patients with primary muscle-invasive bladder cancer (MIBC) in comparison to patients with secondary MIBC after a history of non-muscle-invasive disease. Objective: To investigate pathologic response rates and survival associated with primary versus secondary MIBC among patients treated with cisplatin-based NAC for cT2-4N0M0 MIBC. Design setting and participants: Oncologic outcomes were compared for 350 patients with primary MIBC and 64 with secondary MIBC treated with NAC and radical cystectomy between 1992 and 2021 at 11 academic centers. Genomic analyses were performed for 476 patients from the Memorial Sloan Kettering/The Cancer Genome Atlas cohort. Outcome measurements and statistical analysis: The outcome measures were pathologic objective response (pOR; ≤ypT1 N0), pathologic complete response (pCR; ypT0 N0), overall mortality, and cancer-specific mortality. Results and limitations: The primary MIBC group had higher pOR (51% vs 34%; p = 0.02) and pCR (33% vs 17%; p = 0.01) rates in comparison to the secondary MIBC group. On multivariable logistic regression analysis, primary MIBC was independently associated with both pOR (odds ratio [OR] 0.49, 95% confidence interval [CI] 0.26-0.87; p = 0.02) and pCR (OR 0.41, 95% CI 0.19-0.82; p = 0.02). However, on multivariable Cox regression analysis, primary MIBC was not associated with overall mortality (hazard ratio 1.70, 95% CI 0.84-3.44; p = 0.14) or cancer-specific mortality (hazard ratio 1.50, 95% CI 0.66-3.40; p = 0.3). Genomic analyses revealed a significantly higher ERCC2 mutation rate in primary MIBC than in secondary MIBC (12.4% vs 1.3%; p < 0.001). Conclusions: Patients with primary MIBC have better pathologic response rates to NAC in comparison to patients with secondary MIBC. Chemoresistance might be related to the different genomic profile of primary versus secondary MIBC. Patient summary: We investigated the treatment response to neoadjuvant chemotherapy (NAC; chemotherapy received before the primary course of treatment) and survival for patients with a primary diagnosis of muscle-invasive bladder cancer (MIBC) in comparison to patients with a history of non-muscle-invasive bladder cancer that progressed to MIBC. Patients with primary MIBC had a better response to NAC but this did not translate to better survival after accounting for other tumor characteristics.