Marked differences between PSA testing and prostate cancer diagnosis across different European countries in the past few decades are ‘indicative of overdiagnosis’, researchers have concluded.
While the analysis showed rapid increases in the number of new cases alongside the uptake of mainly opportunistic PSA testing, rates of death from the disease were much lower and showed less variation.
Most countries had seen a steady decline in mortality and there were fewer differences between the 26 countries looked at despite large differences in use of PSA and diagnosis, they researchers showed.
It highlights that any future implementation of prostate cancer screening must be carefully designed particularly with regards to minimising the risk of overdiagnosis which would need to be carefully monitored, they concluded in the BMJ.
The team noted that unregulated and opportunistic PSA testing has been, and still is, common in Europe.
Countries have been advised by the European Commission to take a ‘stepwise approach’ to pilot the feasibility of organised PSA testing programmes in conjunction with MRI follow-up.
Last year the UK National Screening Committee said it was looking at six different proposals for prostate cancer screening, including a targeted service for men at higher risk.
That was followed by the Government announcement of a landmark trial to test screening in men at higher risk of the disease.
The latest analysis, which included figures from the UK, showed that the incidence of prostate cancer more than doubled in most countries from 1990 to 2017, in parallel with uptake of PSA testing.
There were stark differences in the pace across countries and over time with prostate cancer diagnoses highest in northern Europe, France, and the Baltic countries, including in Lithuania where rates increased up to eightfold.
By contrast, mortality rates were lower in absolute terms and with much less variation between the highest and lowest countries.
Across all countries and periods, there was up to a 20-fold variation in prostate cancer incidence, but only a fivefold variation in deaths, they concluded.
While stressing it was an observational study, they said the findings ‘should help to improve the understanding of the effect of PSA testing on incidence and mortality in Europe by highlighting consistent patterns across countries’.
‘The current high incidence of prostate cancer in many countries may be inflated by unregulated and opportunistic PSA testing that serves to mask any variations due to causal factors and may be indicative of overdiagnosis,’ they added.
Professor Willie Hamilton, professor of primary care diagnostics at the University of Exeter, said by and large he agreed with the authors’ conclusion.
‘When large changes in incidence are not accompanied in parallel changes in mortality, then there’s one of two mechanisms happening.
‘Either this is overdiagnosis of cancers which won’t threaten life, as happened with some types of thyroid cancer when neck ultrasound mushroomed, or successful identification and early treatment of cancers. It can be a mixture of both.
‘The authors argue for overdiagnosis, and most of us agree it will be a large part of the explanation.
‘It may not be the full explanation, so it is key that good downstream diagnostic facilities are in place (MRI pre-biopsy is a real plus) and that we tease out clinically-relevant cancers from the less relevant ones.’
This excellent study highlights the dangers of poor quality “screening”.
The glut of well meaning celebs to hound anxious healthy men to “get checked” has caused a surge in inappropriate PSA testing, which as we all know lacks the specificity and sensitivity to qualify as effective screening.
As a result a few men are falsely reassured, whilst increasing numbers are put through months or years of fretting over repeated PSA testing, inappropriate scanning or painful biopsies that were probably never indicated.
Hopefully the TRANSFORM trial will bring accurate screening soon, but until then GPs have the difficult task of explaining the pros/cons of random PSA testing. Nobody wants a patient talked out of a PSA returning years later with a cancer diagnosis, so the temptation is to give in and test.