Prostate cancer risk profiles of Asian-American men: disentangling the effects of immigration status and race/ethnicity.

PURPOSE: Asian-American men with prostate cancer have been reported to present with higher grade and later stage disease than white American men. However, Asian-American men comprise a heterogeneous population with distinct health outcomes. We compared prostate cancer risk profiles among the diverse racial and ethnic groups in California.
MATERIALS AND METHODS: We used data from the California Cancer Registry on 90,845 nonHispanic white, nonHispanic black and Asian-American men diagnosed with prostate cancer between 2004 and 2010. Patients were categorized into low, intermediate and high risk groups based on clinical stage, Gleason score and prostate specific antigen at diagnosis. Using polytomous logistic regression we estimated adjusted ORs for the association of race/ethnicity and nativity with risk group.
RESULTS: In addition to the nonHispanic black population, 6 Asian-American groups (United States born Chinese, foreign born Chinese, United States born Japanese, foreign born Japanese, foreign born Filipino and foreign born Vietnamese) were more likely to have an unfavorable risk profile compared to nonHispanic white men. The OR for high vs intermediate risk disease ranged from 1.23 (95% CI 1.02-1.49) for United States born Japanese men to 1.45 (95% CI 1.31-1.60) for foreign born Filipino men. These associations appeared to be driven by higher grade and prostate specific antigen rather than by advanced clinical stage at diagnosis.
CONCLUSIONS: In this large, ethnically diverse, population based cohort Asian-American men were more likely to have an unfavorable risk profile at diagnosis. This association varied by racial/ethnic group and nativity, and was not attributable to later stage at diagnosis. This suggests that Asian men may have biological differences that predispose to more severe disease.