Association of asymptomatic PSA testing on prostate cancer mortality; a case control study in general practice

Background PSA is not recommended for screening by The UK National Screening Committee due to risks of over-diagnosis and over-treatment. However, men in England aged 50+can request a PSA test from their GP.

Aimes To investigate the association between PSA and cancer mortality and estimate the absolute and relative risk of prostate cancer deaths.

Design & setting Nested case–control study using the Clinical Practice Research Datalink (CPRD) GOLD database.

Method Cases were men who died of prostate (2003-2018) cancer aged 55-84. Age and sex-matched controls were selected from men without prostate cancer death. Odds ratios (OR) were estimated using conditional logistic regression, adjusting for age, socioeconomic deprivation, body mass index, and practice-level PSA testing rate. Ten-year absolute risk of prostate cancer mortality was calculated using weighted OR calibrated to national mortality rates.

Results Among 2,919 cases and 8757 controls, men with a “screening” PSA test were 33% (OR=0.67, 95% CI: 0.56-0.80) less likely to die from prostate cancer than not tested. Men aged 65-74 with a PSA<2 ng/mL had a 0.15% 10-year mortality risk versus 0.8% in those not tested. Men in practices in the top 20% for PSA testing were 10% (95%CI: -5 to 23%) less likely to die of prostate cancer than those from the bottom 20%.

Conclusions PSA testing was associated with lower prostate cancer mortality, while higher PSA level was linked to increased risk. Higher primary care use of PSA testing was associated with improved patient outcomes. These findings support consideration of risk- stratified screening rather that a uniform approach.