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Screening ‘significantly reduces deaths from prostate cancer’

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The long-running European Randomised Study of Screening for Prostate Cancer (ERSPC) last week published its 11-year follow-up results, which add weight to their original findings by confirming that screening does significantly reduce deaths from prostate cancer.


 

Published in the New England Journal of Medicine, the study finds that a man who undergoes prostate-specific antigen (PSA) testing will have his risk of dying from prostate cancer reduced by 29 per cent.

Screening for prostate cancer is controversial. Prostate cancer can develop so slowly that it will never cause problems during a man’s lifetime. A major consideration for any national screening protocol, regardless of disease type, is to weigh up the possibility someone will have needless treatment against saving lives.

“The difficulties around screening for prostate cancer occur because the PSA test is not a specific test for prostate cancer; it can only indicate that a man may have a problem with his prostate gland that needs further investigation. Up to two-thirds of men with a raised PSA do not have prostate cancer, therefore routine PSA testing of all men could lead to much anxiety and alarm,” concluded a 2010 analysis on the subject. The US Preventive Services Task Force continued: “The evidence is insufficient to recommend for or against routine screening for prostate cancer using PSA testing or digital rectal examination (DRE).”

Many doctors also argue against PSA testing for men who are in their 70s or older, because even if prostate cancer were detected, most men could be dead of something else before the cancer progressed. Others argue against PSA testing for men who are too young, because too many men would have to be screened to find one cancer, and too many men would therefore have treatment for cancer that would not progress.

The European Randomised Study of Screening for Prostate Cancer, initiated in the early 1990s, aimed to evaluate the effect of screening with PSA testing on death rates from prostate cancer. The trial involved 182,000 men between the ages of 50 and 74 years in seven European countries randomly assigned to a group that was offered PSA screening at an average of once every four years or to a control group that did not receive such screening.

During a median follow-up of almost nine years, the cumulative detected incidence of prostate cancer was 820 per 10,000 in the screening group and 480 per 10,000 in the control group. Deaths from these cancers in this time was much lower.

There were 214 prostate cancer deaths in the screening group and 326 in the control group, a difference of 7.1 men per 10,000 in the tested group compared to the control. The researchers concluded two years ago that PSA-based screening did reduce the rate of death from prostate cancer by 20 per cent, but that this was associated with a high risk of over-diagnosis: 1,410 men would need to be screened and 48 additional cases of prostate cancer would need to be treated to prevent just one death from prostate cancer.

Now, the 11-year follow-up results have confirmed that a man who undergoes PSA testing will have his risk of dying from prostate cancer reduced by 29 per cent. By extending the patient follow-up to an average of 11 years, the study shows that 31 per cent fewer men than previously indicated would need to be diagnosed with cancer to save one life.

As Professor Fritz Schroeder, the international coordinator of the ERSPC study and Professor of Urology, Erasmus Medical Centre, The Netherlands, explains: “Extending the follow-up period strengthens the argument for screening. But it does not decide it. Even so, the risk reduction trend in our study is promising and it is imperative that we continue the follow-up. So far, only about 30 per cent of all men in the study have died. If a larger reduction of prostate cancer mortality is seen by further extending the study beyond the current median of 11 years, we can determine with greater certainty whether the benefit of screening outweighs the disadvantages.

“Screening programmes for prostate cancer will not be feasible until the medical communities can confidently balance the risk of reducing death from prostate cancer with these unacceptably high levels over diagnosis and overtreatment,” adds Prof Schroeder.

Compared with the US, individual PSA testing started late in most European countries and meant that only a relatively small number of men taking part in the control arm of the ERSPC study had previously taken a PSA test.

“This makes the ERSPC study fundamentally different from the US-based Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer screening trial where there was a high contamination rate in the control arm, with at least 44 per cent of participants already PSA-tested prior to being randomised into the study,” says Prof Schroeder.

The PLCO study has been unable to demonstrate any difference in prostate cancer mortality between the two arms of the study.

The ERSPC study and the PLCO study are the scientific world’s main chances to determine the benefits of screening for prostate cancer.

If a relevant difference of 20 per cent or more is shown in these trials at an acceptable cost in terms of quality of life and money, it can be expected that governments worldwide will introduce screening programmes for prostate cancer, which will then be included into paid healthcare policy packages.

“The great hope of all investigators is that this in fact will happen and that early diagnosis can be offered to all men at risk to decrease the burden of suffering and potential death from prostate cancer,” says Pror Schroeder.

 

 

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