Changes in case mix and treatment patterns in prostate cancer in Saskatchewan during the prostate specific antigen testing era

Abstract

Background: The prostate specific antigen (PSA) test became available in Saskatchewan in 1990 as a part of the provincial health plan. The purpose of this population-based study was to describe the changes in case mix and treatment patterns for prostate cancer following its introduction.

Methods: The Saskatchewan Cancer Registry was used to identify all new cases of prostate cancer for the period 1985-2001. We reviewed over 10,000 charts to collect information on tumor characteristics, diagnostic methods, and first choice of treatment. This information was linked to the demographic and mortality data from the registry.

Results: The age-adjusted incidence of prostate cancer was influenced greatly by PSA testing volumes. Overall, the rate increased from 90.3 per 100,000 in 1985 to 151.3 per 100,000 in 2001. The increase was mostly organ-confined moderately differentiated cases. The incidence rate of metastatic disease dropped about 50% but only in the 70-79 and 80+ age groups. In 1985, 34% of cases were diagnosed by needle biopsy and 60.4% by TURP. In 2001, the values were 76.1% and 19.7%, respectively. More men now choose radical therapy as the first course of treatment, 81% during 1997-2001 compared to only 63.2% in the 1985-1989 period. Mortality rates remained stable in all age groups over these years.

Conclusion: There have been dramatic changes in the case mix of prostate cancers diagnosed since the introduction of PSA testing in the population and significant changes in clinical management of this disease. Thus far, no changes have occurred in mortality rates in the population.