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Screening could cut prostate cancer deaths by a fifth

But over-diagnosis still an issue; not yet time to roll out national programmes, say researchers

Caroline White

Thursday, 07 August 2014

Prostate cancer screening could cut deaths from the disease by around a fifth, finds a large European study*, published in The Lancet.

But routine prostate specific antigen (PSA) screening should not be introduced, because it remains unclear whether the pros outweigh the cons, conclude the researchers.

The European Randomised study of Screening for Prostate Cancer (ERSPC) began in 1993 to find out whether screening men for PSA reduces deaths from prostate cancer.

It recruited 162,000 men between the ages of 50 and 74 years from Belgium, Finland, France, Italy, Netherlands, Spain, Sweden, and Switzerland who were randomly assigned to receive either PSA screening every 4 years (2 years in Sweden), or nothing. Men were referred for biopsy if their PSA level rose above 3 ng/ml.

Screening seemed to reduce prostate cancer deaths by 15% at 9 years, and this improved to 22% at 11 years.

But there was no further improvement at 13 years in the relative reduction in prostate cancer deaths which fell by a fifth (21%) in the screening group compared with the comparison group, although men who were screened had a 27% lower chance of dying of the disease.

But the absolute benefit of screening rose steadily, the longer the monitoring period. The number of men needed to be screened to prevent one death from prostate cancer plummeted from 1,410 after 9 years of monitoring to 781 at 13 years.

Similarly, the number needed to be diagnosed and treated to prevent one prostate cancer death also fell from 48 to 27. The risk of advanced prostate cancer was also smaller in the screening group.

Lead author Professor Fritz Schröder from Erasmus University Medical Center in the Netherlands, said: “PSA screening delivers a substantial reduction in prostate cancer deaths, similar or greater than that reported in screening for breast cancer. However, over-diagnosis occurs in roughly 40% of cases detected by screening, resulting in a high risk of overtreatment and common side-effects such as incontinence and impotence.”

He added: “The time for population-based screening has not arrived. Further research is urgently needed on ways to reduce over-diagnosis preferably by avoiding unnecessary biopsy procedures, and reducing the very large number of men who must be screened, biopsied, and treated to help only a few patients.”

One promising approach is multiparametric MRI technology which may be able to selectively diagnose aggressive prostate cancers and avoid the diagnosis of many inconsequential tumours that generally grow so slowly that most men will die of other causes, he said.

Dr Iain Frame, Director of Research at Prostate Cancer UK, commented: “These results are no great surprise and highlight yet again the urgent need for a test which can distinguish between dangerous cancers that could go on to kill and those which may never cause any harm.

“Without a reliable test, the introduction of a screening programme could mean an enormous rate of over diagnosis and therefore over treatment of potentially harmless cancers – outweighing any benefits that a screening programme might bring.”

* Prof Fritz H Schröder Screening and prostate cancer mortality: results of the European Randomised Study of Screening for Prostate Cancer (ERSPC) at 13 years of follow-up. The Lancet, Early Online Publication, 7 August 2014. doi:10.1016/S0140-6736(14)60525-0

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