Fewer Men Are Dying
From 1977 to about 1990, there was a gradual increase in prostate cancer mortality rates. The rate of increase sped up slightly in the mid 1980s, but then mortality rates began to drop slightly beginning in 1992 for Caucasian men and 1994 for African American men. The overall rate declined 6.3% from 1991 to 1995. While it seems that increased screening may be responsible for the reduction in death rate, it may not because of two reasons:
1. PSA screening detects prostate cancer at least 5 years earlier than it would have been detected otherwise (from symptoms or by digital rectal exam). Mortality from a PSA-detected cancer that could be prevented by early treatment would take place only after this 5-year lead-time had passed. But the drop in mortality rates has occurred extremely quickly compared to the estimated average lead-time. The fact that the decline occurred so soon after the popularization of the PSA test casts serious doubt that it was due to the increased use of the test.
2. A recently diagnosed cancer may be recorded as cause of death, even if, as in the case of preclinical prostate cancers, it is almost certainly not the true cause of death. The death of an elderly man might thus be wrongly attributed to prostate cancer simply because a recent diagnosis is in his files and no other underlying cause could be identified. There was a sharp increase in new diagnoses of preclinical prostate cancer after 1989 with the boom in PSA testing. But, after the initial spike in incidence began to fall off in 1992, there were fewer men with recent diagnoses of prostate cancer, and consequently, fewer deaths might have been incorrectly attributed to prostate cancer.
