Gender, Racial and Ethnic Differences in Pathologic Response Following Neoadjuvant Chemotherapy for Bladder Cancer Patients

Abstract

To evaluate trends and racial variations of pathologic complete response (CR) in patients with muscle-invasive bladder cancer undergoing cystectomy. The National Cancer Database was queried for patients with non-metastatic muscle-invasive bladder cancer who underwent neoadjuvant chemotherapy and surgery. The primary endpoints, CR and mortality, were evaluated using the Cochran-Armitage test, multivariable regression, and Kaplan-Meier analyses. The cohort comprised 9955 patients. Non-Hispanic Black (NHB) patients were younger (P < .001), had a higher clinical tumor (P < .001), and had higher clinical node(P = .029) stages at presentation. CR for non-Hispanic White (NHW), NHB, and Hispanic patients were 12.6%, 10.1%, and 11.8%, respectively (P = .030). There was a significant increase in CR trends for NHW patients (P < .001) and increases in NHB (P = .311) and Hispanic patients (P = .236). On multivariable analysis, NHW females had lower odds of achieving CR (odds ratio: 0.83, 95%CI: 0.71-0.97); however, NHB males (hazard ratio: 1.21, 1.01-1.44) and NHB females (hazard ratio: 1.25, 1.03-1.53) had higher overall mortality in adjusted analysis. Survival differences were not observed in patients who achieved CR, regardless of racial background; however, for those with residual disease, the 2-year survival probabilities were 60.7%, 62.5%, and 51.1% for NHW, HW, and NHB patients, respectively (log-rank P = .010). Our findings revealed differences in chemotherapy response based on gender and race or ethnicity. The CR trends for all racial or ethnic groups increased over time. However, Black patients were found to have worse survival, particularly when residual disease was present. Clinical studies with more underrepresented minorities are needed to verify biological differences in response to neoadjuvant chemotherapy.