Geographical and Temporal Distribution of Prostate Specific Antigen Testing Across Australia

Abstract

Prostate cancer is the second most diagnosed cancer worldwide among men and the most diagnosed in Australia. Despite controversies surrounding its low specificity, the Prostate-specific antigen (PSA) test remains the most commonly used test for prostate cancer. In Australia, PSA “screening” test rates have consistently been high among men living in socio-economically advantaged and urban areas compared to disadvantaged and rural areas. Long term national level data on these trends has not been available. Additionally, there is limited information about the prevalence of PSA testing at the small geographical area level, limiting the ability to appropriately understand the role of PSA testing in the observed geographical patterns of prostate cancer incidence. The aim of this thesis was to investigate spatial and temporal patterns of PSA testing in Australia.

We utilized the population-based Medicare Benefit Schedule dataset on PSA testing, developed complex methods to transform postcodes into smaller areas and used Bayesian models to identify key underlying patterns. We first computed a general PSA testing trend across Australia, as well as by area-specific regions, including socio-economic status, remoteness, and states and territories. Then, we investigated whether the national patterns were evident in smaller areas across Australia over time. Finally, to understand the impact of PSA testing on prostate cancer incidence, we examined the association between PSA testing and prostate cancer incidence by small areas.

This population-based study identified substantial variation in the participation rate of PSA testing by small geographical areas across Australia and over time. However, there was a low association between PSA testing and prostate cancer incidence at the smaller area level. This information can help in reviewing and developing evidence-based strategies to reduce any identified disparities in prostate cancer indicators across Australia.