The role of prostate-specific antigen (PSA) testing patterns in the recentprostate cancer incidence decline in the United States

Objectives: Trends in first-time and later PSA procedure rates are ascertai ned using longitudinal data from a population-based cohort. These trends ar e compared to trends in prostate cancer incidence to determine the role of PSA in the recent decline in prostate cancer incidence. Methods: Medicare data were linked with tumor registry data from the Nation al Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Pr ogram. A 5 percent random sample (n = 39 985) of Medicare beneficiaries fro m the SEER areas without a previous diagnosis of prostate cancer as of Janu ary 1, 1988 was followed through 1994. Trends in first-time PSA use were di stinguished from those of second or later for men without diagnosed prostat e cancer. Results: Trends in the rate of first-time PSA procedures track closely with trends in prostate cancer incidence rates, increasing until. 1992 and decr easing thereafter. Similar patterns were observed by race and age group. Ge ographic variability in the dissemination of PSA screening was observed, ye t the association between testing and incidence remained. Men in the cohort had a 4.7 percent chance of being diagnosed within three months of an init ial PSA test, with the percentage falling for subsequent tests. Conclusions: It is informative to distinguish first from later tests when a ssessing the effect of the diffusion of a test in a population. Taking this approach was useful in illuminating the role of PSA testing in a reversal of a long-term increase in prostate cancer incidence rates.