Rates of prostate cancer across Europe – since 1980 – are “indicative of over-diagnosis”, say researchers, who suggest this “may be inflated by unregulated and opportunistic PSA testing”.
Over-diagnosis refers to the detection of harmless cancers that are unlikely to cause symptoms or death during a patient's lifetime, which can lead to unnecessary treatment, negative impacts on quality of life, and wasted healthcare resources.
The findings, by an international team of experts and published in The BMJ, show rapid increases in the number of new cases (incidence) in parallel with uptake of so far predominantly opportunistic prostate specific antigen (PSA) testing. Yet death rates during 1980-2020 were much lower and less variable, with steady declines in most countries and fewer differences between countries, reports Medical-News.net.
This divergence between incidence and deaths “suggests that the intensity and coverage of PSA testing has been a critical driver for the increasing trends in prostate cancer incidence in Europe”, said the researchers, which reinforces the need to minimise harms of over-diagnosis.
This is of particular relevance for the potential implementation of population-wide prostate cancer screening programmes, which, if implemented in the future, should be carefully designed and planned to minimise and monitor the harms of over-diagnosis in the population, they added.
Unregulated and opportunistic PSA testing has been, and still is, common in Europe.
The EU Beating Cancer Plan recently proposed a new strategy for prostate cancer screening programmes, but baseline data on national levels and trends in prostate cancer outcomes are needed before new approaches are introduced.
To do this, researchers obtained data on annual incidence rates of prostate cancer for men aged 35-84 in 26 European countries from 1980-2017 and mortality data from 1980-2020. They also carried out a review of studies on uptake of PSA testing across 12 European countries.
They found that incidence more than doubled in most countries from 1990 to 2017, in parallel with uptake of PSA testing, although the pace of increase varied greatly across countries and over time.
For example, increases in incidence were highest in northern Europe, France, and the Baltic countries, notably in Lithuania where rates increased up to eightfold. The difference between the highest and lowest incidence rates across countries ranged from 89.6 per 100 000 men in 1985 to 385.8 per 100 000 men in 2007.
In contrast, death rates were much lower in absolute terms, spanning from 12 (Ukraine and Belarus) in 1981 to 53 (Latvia) deaths per 100 000 men in 2006. The difference between the highest and lowest death rates across countries ranged from 23.7 per 100 000 men in 1983 to 35.6 per 100 000 men in 2006.
Considering all countries and periods, there was up to a 20-fold variation in prostate cancer incidence, but only a five-fold variation in deaths.
This is an observational study so no firm conclusions can be drawn about cause and effect, and the researchers pointed to several limitations that mean the findings should be interpreted with caution.
Nevertheless, they said these results “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 over-diagnosis,” they said.
“Careful monitoring and assessment of the benefits and harms, including over-diagnosis, will be essential for the potential implementation of EU guidelines and the prospective introduction of population-wide prostate cancer screening.”
Study details
Prostate cancer incidence and mortality in Europe and implications for screening activities: population-based study
Salvatore Vaccarella, Mengmeng Li, Luigino Dal Maso, et al.
Published in The BMJ on 4 September 2024
Abstract
Objective
To provide a baseline comparative assessment of the main epidemiological features of prostate cancer in European populations as background for the proposed EU screening initiatives.
Design
Population-based study.
Setting
26 European countries, 19 in the EU, 1980-2017. National or subnational incidence data were extracted from population based cancer registries from the International Agency for Research on Cancer’s Global Cancer Observatory, and mortality data from the World Health Organization.
Population
Men aged 35-84 from 26 eligible countries.
Results
Over the past decades, incidence rates for prostate cancer varied markedly in both magnitude and rate of change, in parallel with temporal variations in prostate specific antigen testing. The variation in incidence across countries was largest around the mid-2000s, with rates spanning from 46 (Ukraine) to 336 (France) per 100 000 men. Thereafter, incidence started to decline in several countries, but with the latest rates nevertheless remaining raised and increasing again in the most recent quinquennium in several countries. Mortality rates during 1980-2020 were much lower and less variable than incidence rates, with steady declines in most countries and lesser temporal differences between countries. Overall, the up to 20-fold variation in prostate cancer incidence contrasts with a corresponding fivefold variation in mortality. Also, the inverse U-shape of the age specific curves for incidence contrasted with the mortality pattern, which increased progressively with age. The difference between the highest and lowest incidence rates across countries ranged from 89.6 per 100 000 men in 1985 to 385.8 per 100 000 men in 2007, while mortality rates across countries ranged from 23.7 per 100 000 men in 1983 to 35.6 per 100 000 men in 2006.
Conclusions
The epidemiological features of prostate cancer presented here are indicative of over-diagnosis varying over time and across populations. Although the results are ecological in nature and must be interpreted with caution, they do support previous recommendations that any future implementation of prostate cancer screening must be carefully designed with an emphasis on minimising the harms of over-diagnosis.
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