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 rela te these to prostate-specific antigen (PSA) testing for prostate cance r. Design: Descriptive study based on data from the Western Australian Cancer Registry, the Australian Bureau of Statistics and the Health I nsurance Commission. Data: All newly diagnosed cases of prostate cance r and ail deaths from prostate cancer in Western Australia from 1985 t o 1996. Main outcome measures: Recorded incidences and mortality rates for prostate cancer. Results: After increasing steadily from 42 per 1 00000 person-years in 1985 to 61 in 1992, the recorded incidence more than doubled to 134 per 100000 person-years in 1994, then fell sharply to 87 in 1996. Among men aged 50 years or more, those aged 50-54 year s 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 1 994. 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 mor tality rate increased annually by 2.9% (95% CI, 2%-4%) from 1985 to 19 96. The number of Medicare reimbursements for PSA tests increased unti l 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 in cidence of prostate cancer increased dramatically in 1992 because of s creening by PSA testing. From 1994, these incidence figures declined a lmost as sharply, partly because of reductions in testing. The mortali ty rate has not shown any systematic deviation from its long-term tren d.