More Men Are Being Diagnosed
The incidence of prostate cancer in the U.S. increased gradually from the 1970s to the late 1980s. Then after 1989, incidence rates rose sharply, but then began falling sharply after 1992. For Caucasian men, the incidence rate peaked in 1992 at 185.8 new cases per 100,000 men before dropping 27% to 135.3 new cases per 100,000 in 1994. Incidence in African American men peaked in 1993 at 264.7 cases per 100,000 before declining 11% to 234.4 cases per 100,000 in 1994. There is general agreement that increased use of PSA testing after 1989 created an artificial rise in incidence rates.
Physicians increased their use of the PSA test for men age 65 and older -- the age group most susceptible to prostate cancer -- from 1,430 tests per 100,000 men in 1988 to 18,000 per 100,000 men in 1991. The subsequent fall in incidence also may be a result of changing PSA screening patterns. A first round of screening picks up long latent as well as more recent cancers and creates a spike in incidence rates. But if the rate of first-time screening drops, the incidence rate also can be expected to drop because first-time screening yields more cancers than subsequent screening. Researchers at the National Cancer Institute are investigating PSA screening among Medicare patients, to try to separate out the early screens from later ones to better understand the relationship between PSA testing and prostate cancer incidence.
