Racial/ethnic disparities in penile squamous cell carcinoma incidences, clinical characteristics, and outcomes: A population-based study, 2004-2016

Purpose: This study assessed the impact of race/ethnicity on penile squamous cell carcinoma (PSCC) incidence rates, clinical characteristics, and outcomes.

Materials and methods: Surveillance, Epidemiology and End Results data from 2004 to 2016 was used for this study. We evaluated racial/ethnic differences in clinical characteristics using χ² tests. Overall survival (OS) and PSCC-specific survival (PSCC-SS) were estimated using the Kaplan-Meier method, and differences were determined using the log-rank test. Cox regression models were performed to assess independent predictors for PSCC patient survival.

Results: A total of 2,720 PSCC patients were included for incidence analysis, and 2,438 patients were identified for the χ² testing and survival analyses.The overall incidence of PSCC during 2004 to 2016 was 0.30 per 100,000. Only non-Hispanic white (NHW) patients had a statistically significant increase in age-adjusted incidence rates (annual percent change = 2.26, 95% confidence interval [CI]: 0.78-3.76; P = 0.01). In univariate analysis, race/ethnicity was an independent prognostic factor for OS and PSCC-SS. After adjusting for age, marital status, income, grade, TNM (tumor, node, metastasis) stage, and treatment strategies, non-Hispanic black patients still had a statistically significant hazard ratio of 1.35 (95% CI: 1.08-1.68; P = 0.007) for OS, and a hazard ratio of 1.36 (95% CI: 1.01-1.82; P = 0.045) for PSCC-SS compared to NHW.

Conclusion: NHW patients had a statistically significant increase in age-adjusted incidence rate during the period 2004 to 2016. Race/ethnicity is an independent prognostic factor for OS and PSCC-SS, and non-Hispanic black were proven to have unfavorable OS and PSCC-SS compared with NHW.