Findings from a prostate cancer screening program in a Japanese population

A remarkable finding in this study is that the age-adjusted “cut-off ” PSA levels in Japanese men in this cohort, was lower than the PSA levels in European and Middle-Eastern men, but appeared to be similar to that of Chinese and Korean men. Studies have previously demonstrated an increased incidence of prostate cancer in Asian-American men compared with men living in Asia, thought to be attributed to environmental factors.5 While, Kitagawa et al.2 acknowledge that factors such as body mass and weight (not accounted for) could have affected PSA levels in their study, they suggest that changes in diet and lifestyle may affect serum PSA levels in middleaged men, which could help explain the differences in prostate cancer incidence between the native and migratory Asian men. Thus, these regional variations in PSA levels could play a role in determining region-specific “cut-off ” levels of PSA, in addition to the age-specific PSA levels in different populations. However, further studies are needed to validate this noteworthy finding. Despite the inherent limitations of a retrospective populationbased study, Kitagawa et al.2 demonstrates some interesting features in the PSA screening program in a Japanese population, adding to the existing body of literature on population-based screening for prostate cancer.