Assessing genetic lifetime risk for prostate cancer has been proposed as a means of risk stratification to identify those for whom prostate-specific antigen (PSA) testing is likely to be most valuable. This project aimed to test the effect of introducing a genetic test for lifetime risk of prostate cancer in general practice on future PSA testing.
We performed a cluster randomized controlled trial with randomization at the level of general practices (73 in each of two arms) in the Central Region (Region Midtjylland) of Denmark. In intervention practices, men were offered a genetic test (based on genotyping of 33 risk-associated single nucleotide polymorphisms) in addition to the standard PSA test that informed them about lifetime genetic risk of prostate cancer and distinguished between "normal" and "high" risk. The primary outcome was the proportion of men having a repeated PSA test within 2 years. A multilevel logistic regression model was used to test the association. After applying the exclusion criteria, 3,558 men were recruited in intervention practices, with 1,235 (34.7%) receiving the genetic test, and 4,242 men were recruited in control practices. Men with high genetic risk had a higher propensity for repeated PSA testing within 2 years than men with normal genetic risk (odds ratio [OR] = 8.94, p < 0.01). The study was conducted in routine practice and had some selection bias, which is evidenced by the relatively large proportion of younger and higher income participants taking the genetic test.
Providing general practitioners (GPs) with access to a genetic test to assess lifetime risk of prostate cancer did not reduce the overall number of future PSA tests. However, among men who had a genetic test, knowledge of genetic risk significantly influenced future PSA testing.
This study is registered with ClinicalTrials.gov, number NCT01739062.
PLoS medicine. 2020 Feb 07*** epublish ***
Jacob Fredsøe, Jan Koetsenruyter, Peter Vedsted, Pia Kirkegaard, Michael Væth, Adrian Edwards, Torben F Ørntoft, Karina D Sørensen, Flemming Bro
Department of Clinical Medicine, Aarhus University, Aarhus, Denmark., Research Unit for General Practice, The Research Centre for Cancer Diagnosis in Primary Care (Cap), Aarhus University, Aarhus, Denmark., Department of Public Health, Randers Regional Hospital, Randers, Denmark., Department of Public Health, Section of Biostatistics, Aarhus University, Aarhus, Denmark., Division of Population Medicine, School of Medicine, Cardiff University, Cardiff, United Kingdom.