Widespread PSA testing for prostate cancer causes overdiagnosis in Europe
According to the international study, the widespread use of prostate-specific antigen (PSA) testing has significantly increased the incidence of prostate cancer in Europe. As a result, the disease burden has increased without clear evidence of the benefits of diagnosing the disease.
The research results show that with the widespread use of PSA testing, the incidence of prostate cancer and the number of new cancers have rapidly increased at the population level.
Some prostate cancers are insignificant because they do not progress to a symptomatic stage even when left untreated. Overdiagnosis refers to the detection of cancers that, due to their slow growth, would not cause symptoms or shorten the patient’s life.
The differences in cancer incidence between countries were the greatest around 2005 when they were more than sevenfold. After that, the incidence rate decreased in several countries, but since 2010, the number of new cancers began to increase in Europe again. The study showed considerable variation in the detection of cancers between countries.
Finnish data were not used in the recent study. However, similar changes have been observed also in Finland. The incidence of prostate cancer increased sharply until 2005 and then decreased, while prostate cancer mortality has steadily declined since 1996 (see Finnish Cancer Registry’s cancer statistics).
In European countries, there were significantly fewer deaths than new cancer diagnoses between 1980 and 2020. The incidence of cancer was 5-10 times higher than mortality in many countries.
According to the study, the large number of prostate cancer cases and the significant difference in mortality are due to opportunistic PSA testing, which produces unnecessary cancer diagnoses. Growth in the number of cases was not associated with a decrease in mortality, meaning that the benefits of widespread PSA testing cannot be demonstrated.
However, the researchers point out that the results of the newly published population-level analysis should still be interpreted cautiously. The main purpose of the study was to examine national and regional differences in the prevalence of prostate cancer.
The main goal of screening is to reduce mortality
According to the researchers, opportunistic PSA testing is still common in many European countries. Population-level screenings have not been started in Finland and most of the other countries.
Professor of Epidemiology Anssi Auvinen from Tampere University represented Finland in the research team that conducted the population-level analysis. The study was led by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO).
“The number of prostate cancers is primarily explained by the extent of PSA testing. One could even say that PSA testing caused a prostate cancer epidemic in Europe in the 1990s and 2000s,” Auvinen says.
“Our results highlight that decisions on prostate cancer screening must be carefully planned. The goal of screening is always to reduce mortality, which should be the main criterion for deciding who should be screened. The downside of screening is the detection of indolent cancers, which must be noted in decision-making,” Auvinen adds.
A new screening method for the better identification of prostate cancers
The ProScreen study by Tampere University and the University of Helsinki recently showed that a new three-step prostate cancer screening protocol can identify a significant number of cancers that require treatment and reduce the detection of insignificant cancers with PSA tests. The extent of testing is illustrated by the fact that, in the ProScreen survey, about one in seven men aged 50-63 reported having had a PSA test within the past year, and more than a third within five years.
In the past 10 years, magnetic resonance imaging (MRI) has become an established method of diagnosing prostate cancer. MRI, which was used in the ProScreen study, helps reduce overdiagnosis. In Finland and other Nordic countries, the incidence of prostate cancer has been declining over the past 10 years.
“The more testing is done the more cancers are found. Most cancers detected by PSA testing do not progress during the men’s lifetime, meaning that active treatment is not necessary in their case,” says Professor of Urology Antti Rannikko who leads the ProScreen study together with Auvinen.
Diagnosing low-risk prostate cancer can lead to unnecessary treatments. In such cases, treating the cancer is not beneficia but the treatment itself can deteriorate the patient’s quality of life and incur costs.
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The recent population-level analysis investigated data from 26 European countries, 19 of which were European Union member states. The study researched population-level data on the morbidity and mortality of 35-85-old men. National or regional incidence data were obtained from population-based cancer registries in the Global Cancer Observatory network of the International Agency for Research on Cancer. Mortality data were obtained from the World Health Organization (WHO).
The research results were published in the peer-reviewed The BMJ journal. The prestigious journal and website were previously known as British Medical Journal.
Research article
Prostate cancer incidence and mortality in Europe and implications for screening activities: population based study. BMJ 2024; 386. doi: 10.1136/bmj-2023-077738.
