African descent men (ADM) across the African diaspora have the highest rates of prostate cancer (CaP) of any racial or ethnic group. The incidence rate in African American men (AAM) is 71% higher than in European American men (EAM) and the AAM mortality rate is 210% higher than EAM. Despite the public health implications of these observations, the underlying causes of this disparity remain unresolved, but are likely to involve a complex, multifactorial array of factors: There is substantial evidence that social inequities and access to health care are in part responsible for CaP disparities. Interventions aimed at early detection of CaP (e.g., PSA screening) or PCa treatments have not resulted in a substantial decrease in these disparities, although it is becoming increasingly clear that when screening and treatment are equitably applied, the disparity substantially decreases or disappears. However, while mortality rates have dropped for all men in the past decade, AAM have not experienced the same benefits from screening and early detection as have EAM. Similarly, new surgical, chemotherapeutic, antihormone, and radiological treatments have become available in recent years. These treatments also may not have been equally available to AAM and EAM or have not been optimized to the clinical setting relevant to AAM. For example, AA have different patterns of comorbidity than other groups, which may lead to sub-optimal including of AAM in clinical trials and thus sub-optimal application of these therapies in AAM. The only major risk factors for CaP mortality appear to be race, age, family history, or obesity. Beyond these, there is limited consistent evidence for exposures and environmental factors in CaP etiology or progression. CaP is strongly influenced by biological and genomic variation (germline and tumor), and there is growing evidence that the mutational landscape of prostate tumors varies substantially by race. These observations suggest that biological factors influence CaP incidence and tumor aggressiveness differentially by race and may in part explain CaP disparities by race. It is possible that some men, based on their biomarker profiles, have greater unfavorable prognosis than others, but screening and treatments are applied to all men without regard to their personalized risk profiles. Therefore, all of these factors, interacting with each other in a complex manner, may influence the disparity in CaP deaths between AAM and EAM. The influence of one or more of these factors may be manifest at different stages of the prostate carcinogenesis continuum. Thus, the interventions intended to act on these factors should be designed to target the timing of those influences and be tailored for diverse population groups. Since these factors are largely studied in isolation, it is difficult to optimize the intersectional effects of these factors to reduce CaP disparities.

Citation Format: Timothy Rebbeck. Biological and Social Influences on Disparities in Prostate Cancer Mortality [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr IA43.