Doubts Raised Over US Study on Screening Test

Doubts Raised Over US Study on Prostate Cancer Screening Test

AUCKLAND, Mar. 24 /Medianet International-AsiaNet/ --

The study behind controversial research findings from the US that found a common blood test for prostate cancer has no benefit in reducing deaths has been challenged by Australia’s and New Zealand’s peak body for urological surgeons.

Having carefully reviewed the study into Prostate Specific Antigen (PSA) blood tests undertaken in the United States, the Urological Society of Australia and New Zealand believes that there were design flaws in the US study which invalidate the results.

“We are concerned that Australian men may be persuaded against having a potentially life-saving PSA blood test following media reports of this US study,” said USANZ president, Dr David Malouf.

Dr Malouf, who has just returned from the 24th Annual European Association of Urology Congress in Stockholm, said two studies about the PSA test recently published in the New England Journal of Medicine, one from the US and the other from Europe, had shown very different results and that the conflicting research findings must now be clarified.

“The PLCO study in the US involved 76,000 men and did not demonstrate a benefit from screening. USANZ believes there are fundamental flaws in the study design which make the results of this trial less valid. The follow up of patients enrolled in the study was not of adequate duration and in the non-screened or ‘usual care’ arm of the study more than half of the men underwent PSA testing, thus contaminating the unscreened population” Dr Malouf said.

“By contrast, the ERSPC study in Europe, commencing in the 1990s and involving 162,000 men in 8 European countries, demonstrated that routine prostate cancer screening could cut death rates from the disease by 20%. The study of men aged between 55 and 69 who underwent screening for prostate cancer had a 20% reduction in the risk of dying from prostate cancer compared with men who were not screened. The trial authors estimated that 1400 men would need to be screened to save one life from prostate cancer. These numbers required to save one life are similar to the numbers in breast and colorectal cancer screening programs. While some commentators have argued that many indolent cancers are unnecessarily detected as part of a screening process, in practice many of these men can be reassured and simply monitored without active treatment in the medium and long term”, Dr Malouf said.

Routine population based prostate cancer screening with the PSA blood test is not performed in Australia or New Zealand and is, at present, not advocated by USANZ.

“The position of this professional body remains that patients should have access to PSA based testing if they wish, after discussion with their family doctors and/or specialists about the risks and benefits of such testing.

There is firm data that testing reduces the risk of being diagnosed with advanced disease, and that treating prostate cancers following diagnosis can lead to a reduced risk of dying from the disease compared to no treatment.

The findings of the ERSPC study demonstrates the importance of developing new tests to identify aggressive forms of prostate cancer and differentiate them from more slowly growing tumours. Such a test will enable clinicians to focus treatment on men whose cancers pose a threat to their health and avoid over-treatment of men with the more indolent forms of the disease”, he said.

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