Prostate-Specific Antigen (PSA) Testing
The prostate-specific antigen (PSA) test was approved by the U.S. Food and Drug Administration in 1986 for monitoring disease status in men with prostate cancer and in 1992 for diagnosis. Once approved, the test also was performed on men with urological symptoms as well as on those who were asymptomatic in an effort to diagnose prostate cancer early and affect the mortality rate. Use of the test since 1986 was correlated with a dramatic rise in prostate cancer incidence in the early 1990s, followed by a subsequent decline. Rates have recently resumed the pre-PSA trend. The incidence of distant stage disease, which had been relatively flat, started to decline dramatically in the early 1990s. Prostate cancer mortality also began to decline in the early 1990s, and the decline has continued. Randomized controlled trials have not yet confirmed the efficacy of PSA testing, which raised the question of the role played by the PSA test in the recent mortality decline. It was important that NCI answer this question to provide the public and cancer researchers with an informed judgment about the impact of the PSA test on vital statistics in light of a pattern in the rates that suggested a benefit from use of the test.
Modeling efforts to understand these patterns used data from autopsy studies, SEER, the SEERMedicare linked database, mortality data from the Centers for Disease Control and Prevention, and population estimates from the U.S. Census Bureau. Studies of the incidence patterns estimated that approximately 29 percent of white males and 44 percent of black males were overdiagnosed, an important problem associated with the high prevalence of PSA-detected disease in older men that would not have progressed to symptomatic disease prior to death from other causes. Other findings concluded that if PSA screening was as effective as hypothesized in the major U.S. randomized screening trial, then it could be responsible for a large portion, but not all, of the observed mortality decline. The delay in seeing the full potential mortality benefit of PSA screening is associated with the speed of dissemination of PSA screening, the lead time inherent in screen-detected cases, the size of the survival benefit, and the range of survival times that would have occurred in the absence of screening.
Legler JM, Feuer EJ, Potosky AL, Merrill RM, Kramer BS. The role of prostate-specific antigen (PSA) testing patterns in the recent prostate cancer incidence decline in the United States. Cancer Causes Control 1998;9(5):519-527.
Etzioni R, Legler JM, Feuer EJ, Merrill RM, Cronin KA, Hankey BF. Cancer surveillance series: interpreting trends in prostate cancer. Part III: Quantifying the link between population prostate-specific antigen testing and recent declines in prostate cancer mortality. J Natl Cancer Inst 1999;91(12):1033-1039.
Etzioni R, Penson DF, Legler JM, di Tommaso D, Boer R, Gann PH, Feuer EJ. Overdiagnosis due to prostate-specific antigen screening: lessons from U.S. prostate cancer incidence trends. J Natl Cancer Inst 2002;94(13):981-990.