The safety of England's NHS breast-screening programme is to be reviewed independently in response to allegations that it causes more harm than good.
The decision by National Cancer Director Professor Sir Mike Richards is a victory for critics of the £96m programme who have voiced concerns for over a decade.
But it will alarm the millions of women aged 50 to 70 who are invited for breast screening every three years.
The controversy centres on how many of the "cancers" detected in screening need treating. Critics, led by researchers at the Nordic Cochrane Centre in Denmark, claim that as many as 30 per cent are "overdiagnosed" and would have posed no threat had they remained undetected. But once a woman is diagnosed with cancer, she is set on a path of investigation and treatment, including surgery, chemotherapy and radiotherapy, that may be unnecessary.
A Department of Health spokesperson said: “Our advice has not changed - we urge all women to go for breast screening when invited. The best available evidence shows that screening saves lives by detecting cancers earlier than they would otherwise have been.”
The new review was agreed in September by Professor Richards and Harpal Kumar, chief executive of Cancer Research UK, the country's leading cancer charity, which had expressed growing concern. Professor Richards chose to announce it in a letter to the British Medical Journal (BMJ) published today.
It is a response to a letter to the BMJ by Professor Susan Bewley from the Division of Women's Health at King's College, London, who wrote protesting that Professor Richards had failed to challenge the experts backing breast screening "competently and mercilessly" and demanding "a real, unbiased review that will not be kicked into the long grass". She said the "oft-repeated statement" that breast screening saves 1,400 lives a year had "not been subjected to proper scrutiny".
"Large groups of well-educated, well-intentioned and kind people can be wrong," Professor Bewley added.
The NHS programme claims one life is saved for every 400 women screened over a decade. But critics from the Nordic Cochrane Centre says the true figure is nearer 2,000 women screened for 10 years to save one life. During this time 200 women have to undergo further tests and 10 have to be operated on for breast cancer.
Speaking to The Independent, Professor Richards said: "This is a comprehensive review of the evidence of benefits in terms of how many lives screening saves and the whole question of harms and overdiagnoses. The work is already in hand with the research evidence being collated. This is a broader review of the evidence than has been conducted before, covering both the randomised, controlled trials [that led to the introduction of the national programme] and the evidence of screening in practice."
The conclusions, expected next year, will be presented at a workshop organised by Cancer Research UK for experts on both sides of the debate.
Professor Richards said he took the controversy "very seriously" but warned it might not be possible to achieve consensus.
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