Prostate cancer in Western Australia: trends in incidence and mortality from 1985 to 1996.

Objective: To measure trends in recorded incidence and mortality rates of prostate cancer in Western Australia from 1985 to 1996 and to relate these to prostate-specific antigen (PSA) testing for prostate cancer.
Design: Descriptive study based on data from the Western Australian Cancer Registry, the Australian Bureau of Statistics and the Health Insurance Commission.
Data: All newly diagnosed cases of prostate cancer and all deaths from prostate cancer in Western Australia from 1985 to 1996.
Main Outcome Measures: Recorded incidences and mortality rates for prostate cancer.
Results: After increasing steadily from 42 per 100,000 person-years in 1985 to 61 in 1992, the recorded incidence more than doubled to 134 per 100,000 person-years in 1994, then fell sharply to 87 in 1996. Among men aged 50 years or more, those aged 50-54 years had the largest annual increases: 14% (95% confidence interval [CI], 10%-19%) from 1985 to 1992 and 108% (95% CI, 84%-134%) from 1992 to 1994. They also had the smallest annual decline between 1994 and 1996 (8%; 95% CI, 1% increase to 16% decrease). The mortality rate showed no sudden increases or decreases. In men aged 60 years or older, the mortality rate increased annually by 2.9% (95% CI, 2%-4%) from 1985 to 1996. The number of Medicare reimbursements for PSA tests increased until May 1995, then fell. There was a significant correlation between the monthly number of PSA tests and new cases of prostate cancer (P < 0.01).
Conclusions: Following a period of steady increase, the recorded incidence of prostate cancer increased dramatically in 1992 because of screening by PSA testing. From 1994, these incidence figures declined almost as sharply, partly because of reductions in testing. The mortality rate has not shown any systematic deviation from its long-term trend.