The effect of race/ethnicity on histological subtype distribution, stage at presentation and cancer specific survival in urethral cancer

Objective: To test the effect of race/ethnicity on histological subtype, stage at presentation, and cancer specific mortality (CSM) in urethral cancer patients. Material and Methods: Stratified analyses (Surveillance, Epidemiology and End Results [2004–2016]) tested the effect of race/ethnicity on histology and stage. Cumulative incidence-plots and multivariable competing-risks regression models (CRR), addressed CSM, after matching for TNM-stage, histology, age, and gender. Results: Of 1,904 urethral cancer patients, 71% were Caucasian, 16% African American, 7% Hispanic and 5% other. African Americans were younger (66 years) than Caucasians (73 years) and Hispanics (74 years). In African Americans, adenocarcinoma (25%) and squamous cell carcinoma (SCC; 29%) were more frequent than in Caucasians (12% and 23%) or Hispanics (15% and 20%). African Americans with adenocarcinoma exhibited higher stage than other adenocarcinoma patients. In CRR, African Americans (35%) and Hispanics (29%) exhibited highest and second highest 3-year CSM, even after matching. After further multivariable adjustment of matched CRRs, CSM was higher in Hispanics (HR: 1.93, P= 0.03) and in African Americans (Hazard ratio 1.35, P= 0.07), relative to Caucasians. Conclusion: Race/ethnicity impacts important differences on urethral cancer patients. African American race/ethnicity predisposes to higher rate of SCC and adenocarcinoma. Moreover, African Americans are younger and present with higher stage at diagnoses. Finally, even after most detailed matching for stage, age, gender, and adjustment for treatment and systemic therapy and socioeconomic status, African Americans and Hispanics exhibit higher CSM than Caucasians.