Ethnic-based disparities have been significantly associated with prostate cancer incidence, age and pathological/biochemical presentation, and mortality. Risk for these parameters are lowest in Asian men relative to men of European ancestry, while the highest in men of African ancestry, in particular African-Americans. Limited studies have, however, addressed clinical presentation and contributing factors within the context of Africa. We established the Southern African Prostate Cancer Study (SAPCS), a unique resource to investigate clinical presentation and risk factors within non-migrant Africans. Enrolling over 1000 men to date we report skewing towards significantly higher prostate specific antigen (PSA) levels in cases (83.0% present with a PSA≥20mg/L; median PSA=98.8mg/L) relative to men with no detectable PCa (18.5% present with a PSA≥20mg/L; median PSA=9.1mg/L). Compared with African-Americans, non-migrant Africans presented with significantly more aggressive disease defined by Gleason score >7 (17% and 36%, respectively) and PSA≥20mg/L (17.2% and 83.2%, respectively), which is further exasperated in men from rural versus urban localities. To determine if the observed clinical presentation is driven by genetics and/or environmental factors, we investigated the power for the most significant genome-wide association study (GWAS) identified PCa risk alleles (n=46) as well as epidemiological measures to predict PCa status and/or disease outcomes within the SAPCS. While we show no evidence that previously defined PCa risk alleles predict disease status within Africa, we show associations with family history of cancer, diabetes, current sexual activity and erectile dysfunction, balding pattern, frequent aspirin usage and high PSA levels. We propose that the SAPCS provides a unique non-PSA tested resource to enhance our understanding that drives significant disparities in PCa associated with ethnic background.

Citation Format: Vanessa M. Hayes, Elizabeth A. Tindall, Riana Bornman. Significance of ethnic-based disparities in prostate cancer risk and outcomes. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B22.

©2015 American Association for Cancer Research.
2015