Abstract C055: Determinants of high-risk prostate cancer among African American and White men in California: The RESPOND study (Research on Prostate Cancer in Men of African Ancestry: Defining the Roles of Genetics, Tumor Markers and Social Stress)
Authors: Press David J , Shariff-Marco Salma , Lichtensztajn Daphne Y , Beyer Kirsten , Zhou Yuhong , Gibbon Joseph , DeRouen Mindy C , Pinder Richard , Hamilton Ann S , Haiman Christopher , Cheng Iona , Gomez Scarlett 
Published: September 2020

Abstract
Background: African American (AA) men are more likely than non-Hispanic White (White) men to be diagnosed with high risk prostate cancer (PCa) and are more likely to die of their disease. The reasons for this disparity remain unclear. As AA men are exposed to greater levels of social stressors including structural racism (racial bias and redlining), local segregation, and lower neighborhood socioeconomic status (nSES), these factors may contribute to poorer PCa outcomes. Methods: As part of the RESPOND study, we assembled geocoded data from the California Cancer Registry on all AA and White PCa cases diagnosed 2004-2013. We appended block group data on a composite index of nSES, two measures of structural racism (redlining & racial bias in mortgage lending), two measures of local segregation (typology of racial/ethnic combinations & location quotient (LQ) of relative concentration of AAs in a block group compared to the Metropolitan Statistical Area), and a measure of %AA. Using multivariable logistic regression models adjusted for year and age at diagnosis, marital status, and health insurance type, PCa risk group was modeled as a binary variable based on NCCN criteria that combines PSA, Gleason grade, and TNM stage; these components were also assessed separately as binary outcomes. Results: Among 16,646 AA and 103,078 White PCa cases with measurable NCCN risk, 30.9% of AA and 26.2% of White men were diagnosed with high risk PCa. In multivariable models, residence in the lowest nSES quintile was associated with 1.4 times the odds of high NCCN risk relative to residence in the highest nSES quintile (odds ratio (OR)=1.4, 95% confidence interval (CI)=1.3-1.5 for White men; OR=1.4, 95% CI=1.2-1.6 for AA men). However, after adjusting for nSES, the structural racism and local segregation measures were significantly associated with NCCN risk only among White but not among AA men. Among White men, more pronounced associations with all of these neighborhood factors and high risk PCa were seen in models of high PSA than in models of high grade or advanced stage. Among AA men, the only significant association between any of the structural racism and local segregation measures, independent of nSES, was between redlining and high grade (OR=1.3, 95% CI= 1.1-1.5). In models comparing AA to White men, nSES contributed to nearly 40% of the AA-White disparity in odds of high NCCN risk, with larger contributions to models of PSA than stage or grade. Conclusions: Further research is needed to understand mechanisms for how residence in low SES neighborhoods contribute to the disparity in high risk PCa, especially high PSA, among AA men. Given differential associations of the structural racism and local segregation measures between AA and White men, at least in California data, they are unlikely to be major contributors to racial/ethnic disparities in high risk PCa, independent of nSES. California has less variability in these measures than other states. Expanded analysis with data from the other six RESPOND sites may reveal different results.
Citation Format: David J Press, Salma Shariff-Marco, Daphne Y Lichtensztajn, Kirsten Beyer, Yuhong Zhou, Joseph Gibbon, Mindy C DeRouen, Richard Pinder, Ann S Hamilton, Christopher Haiman, Iona Cheng, Scarlett Gomez. Determinants of high-risk prostate cancer among African American and White men in California: The RESPOND study (Research on Prostate Cancer in Men of African Ancestry: Defining the Roles of Genetics, Tumor Markers and Social Stress) [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C055.