genetic testing – handling the news

genetic testing – handling the news | help and info

a science still in its infancy

While there are obvious benefits to many, there is a very real potential downside to the Government's push for more people to undergo genetic testing to identify whether they are at risk of certain diseases and conditions, experts now warn. Paul Atkinson, a distinguished research professor in sociology from Cardiff University who conducted a three-year study into the impact of genetic testing on people in South Wales, warns that tests to diagnose diseases before patients show symptoms could create a 'nation of panicked people', diverting scarce NHS resources 'away from the genuinely sick to the worried well'.

'Since the genetic science is still in its infancy, population screening exposes people to tentative projections of risk without giving them anything definite to go on,' he explains.

'In the future, when genetic testing is available for a very wide range of conditions, it is possible we could create an unmanageable degree of anxiety in an individual if the proper follow-up services are not available.'

The three-year project at Cardiff University, sponsored by the Economic and Social Research Council, tested a small number of symptomless blood donors for the disorder genetic haemochromatosis, which causes the body to absorb excessive amounts of iron from food and which can lead to liver damage. If diagnosed early, the condition can be easily treated by blood-letting, but left untreated it can cause serious problems, including debilitating arthritis.

Those who were found to be at risk of the disorder, but did not have any symptoms, were not unduly worried about their health, provided they were being monitored and felt that they were being looked after by clinicians. Earlier research involving women at risk of inherited breast cancer, also done in Wales, found that those at the highest risk were less anxious because they were given appropriate support and follow-up. But those women with a lower risk, who were deemed a lower medical priority, were often the most anxious as they did not have access to such support.

importance of counselling

'If genetic screening is to be made to work we will need considerable investment in guidance counselling and follow-up from specialists or general practitioners,' Professor Atkinson explains. 'This is not a panic – more of a warning about the future. The costs will be considerable and may not be the best use of resources, which may be better directed to good diagnosis of the clinical condition.'

Meanwhile, the British Medical Association has warned against screening tests provided by private health companies or bought over the internet, saying they can 'do more harm than good'. An estimated £75 million was spent on private screening in the UK in 2005, up over 10 percent on the previous year. But while patients may pay for the initial screening, if a potential problem is discovered, it is the NHS that picks up the bill for further tests, counselling and treatment.

Dr Vivienne Nathanson, the BMA's head of science and ethics, explains that often private tests pick up something that would never develop into a major health concern. This could result in invasive tests, serious surgery and increased anxiety for patients. 'We want the public to be extremely wary of unregulated screening,' she explains. 'We must make sure the screening is of a high quality and that patients are given all the appropriate advice before they decide to participate.'

Costs for screening vary widely, with BUPA offering around 40 assessments including blood pressure, heart and PSA testing (for prostate cancer) for £395 for men and £425 for women. Other clinics offering comprehensive check-ups, including full body MRI scans, can charge more than £2,000.

Public health consultant Dr Steven Laitner explains: 'A CT scan, which creates a 3-D image of the body, may find something abnormal, for example a small nodule in the lung.

'But to find out if this is something sinister, you might have to have an invasive test to prove it is not lung cancer. Even if it is a cancer, sometimes small cancers go away of their own accord.'

The BMA says formal screening programmes, such as breast checks for women between 50 and 70, have been introduced because they have been proven to be of benefit in detecting disease. However, it adds there are numerous examples where screening is available without such strong evidence to support its use.

Research has shown for example, that mammograms in women under 50 may not detect small cancers, and that it involves a high chance of misleading results. This can lead to further invasive tests and to surgery in many women whose cancers might never have progressed during their lifetime. The use of the PSA test, which is provided on the NHS, is also questioned by the BMA, which says it 'cannot identify those who will die' and warns the treatment of prostate cancer 'has side effects that can cause more problems than the disease'.

Two thirds of men with high PSA do not have prostate cancer, while some men with prostate cancer do not have high PSA. The BMA adds that no evidence exists to show whether treating localised prostate cancer does more good than harm. Concerns were also raised in the report about whole body computer tomography (CT) scans for people without any symptoms – which can cause false alarms and involve significant doses of radiation – and electrocardiograms (ECGs) for people without symptoms of heart disease.

the risks of unregulated testing

The report says unregulated screening can put patients at risk because of a lack of evidence they are effective, no quality control, poor follow up and insufficient information before and afterwards. It also says pre-implantation genetic diagnosis (PGD), now carried out on embryos to see if they carry an inherited disease. Some are concerned it could be used to create 'designer babies' by selecting gender or eye or hair colour, but the BMA says, due to the difficulties involved, PGD is only to be used by couples at serious risk of having a child with a disease, and 'frivolous' use is unlikely.

Dr Nathanson adds there are concerns about the use of information on genetic tests on adults by insurance companies, and says the current moratorium should be used to consider if such information should be treated any differently from other medical data.

'There is no doubt that some specific screening tests have the potential to save lives but this does not mean that there are no associated risks,' she explains. 'We want the public to be extremely wary of unregulated screening. People should be especially cautious about testing kits that can be bought through the internet and mail order.'

The BMA is also worried that even with the existing major programmes the information about the benefits and limitations may be insufficient for patients to make an informed choice based on the harms and benefits of taking part.

Emma Taggart, of Breakthrough Breast Cancer, says: 'We know that mammograms are not as effective in women under 50, as breasts are dense and harder to image. Only women at a higher risk because of their family history are entitled to mammography, in the absence of any breast symptoms, before this age.'

Dr Chris Hiley, of the Prostate Cancer Charity, says: 'There are major uncertainties about the ability of the PSA test to identify correctly men who have prostate cancer and exclude, correctly, men who probably don't have cancer. This is why the PSA test isn't available on the NHS in a screening programme and why we are urging the government to invest in research to find a better, more reliable test.'

Professor Peter Weissberg, Medical Director of the British Heart Foundation says the organisation does not support the indiscriminate use of exercise testing to screen patients with coronary heart disease.

a public debate

But with genetics advancing faster than even those within the field could have imagined 10 years ago, the broader issue of the role and use of genetic testing is becoming increasingly moot.

Sir Paul Nurse, head of Cancer Research UK and winner of the 2001 Nobel Prize for genetic research, says future tests could offer a rundown of each and every gene in a newborn child. 'The fear is that without proper debate and public education people may be written off by insurers and employers because of their DNA,' he says. 'There are several broader questions to consider, including who should decided whether genetic testing takes place, what legislation and regulation we need, what kind of education and information people need to deal with these tests, and how will these tests impact on health and wellbeing?'

There are also psychological questions, he says. 'How do you deal with the knowledge that you might die at 23 or have some ghastly disease at 56?

'Most genetic tests can only indicate a whether or not there is an increased risk, and not whether there's a certainty of developing the disease. There is also added complexity brought about by lifestyle factors – factors we are only just beginning to understand – which may dramatically alter that risk assessment.

'Given this complexity, we need to be extremely careful how this technology is used to shape our society. This is why it is so important to have proper public debate – we need to discuss what genetics can and can't deliver and what sort of society we want as a result.'

(November 2006)

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