Leaders of England's breast-screening programme yesterday accused critics of the tests of using out-of-date data in order to revive alarm that the technique is not credible.
Professor Dame Valerie Beral, chair of the Department of Health's Advisory Committee on Breast Screening, and Julietta Patnick, director of NHS Cancer Screening Programmes, were responding to a review in the British Medical Journal which claimed that the harm caused by breast screening is as great as the benefit. The review was reported in The Independent yesterday.
Klim McPherson, professor of public health epidemiology at the University of Oxford, said in his review that individual women benefited little from breast screening but this was "not widely understood". At the same time he said there was "some possibility of harm" and that the national programme, launched in 1988 and costing £75m a year, was of "marginal cost effectiveness". Two million women a year undergo the screening.
Professor Beral, director of the Cancer Epidemiology Unit at the University of Oxford, said yesterday that the breast-screening advisory committee, composed of 23 experts, had reviewed the evidence in 2006 and published a 54-page report which was not mentioned in Professor McPherson's paper this week.
The report found "clearly reduced mortality from screening" – the equivalent of 1,400 lives saved each year. For each death averted, there were 18 years of life gained on average, at a cost of £3,000 a year in expenses to the screening programme.
An earlier review in 2002 by the International Agency for Research on Cancer, composed of 27 experts from around the world, concluded that screening cut deaths in the 50-69 age group by 35 per cent.
Professor Beral said: "What Klim McPherson and other critics have done is used old data from the US and Scandinavia, largely from the 1970s and 1980s. We looked at data from England, with current treatment and current rates of diagnoses.
"The full report was made publicly available and a summary published in the Journal of Medical Screening. It is reasonable to ask why [McPherson] didn't refer to it. All the questions he raises have been reviewed. Why do we see the same old data rehashed over and over again?"
She said the controversy over breast screening had started in 2000, when critics questioned whether it saved lives, but had since shifted to asking whether the price, in terms of harm caused, was too high.
"The majority of our 2006 report dealt with the harms. In the old days women had mastectomies for breast cancer – now they don't [in cases where the tumour is small enough] so the harms have reduced," she said. "There are claims that cancer is over-diagnosed – but it's a misnomer. We don't know there are some cancers that won't progress – it is an unanswerable question. There are some women who have a breast cancer diagnosis but die of something else, that we know. But it is not true to say that a cancer diagnosed would not have progressed if they had lived longer, we don't know that."
She added: "We would withdraw the programme if there was evidence that we should."
Julietta Patnick said: "How many women do you have to save to make [breast screening] worthwhile? Most women we screen do not have breast cancer, will never get it or die from it.
"But for the 1,400 whose lives are saved, that is 100 per cent of their lives. It makes an enormous difference to them. Women know they are not likely to benefit, but they also know they could be among those 1,400."
Professor McPherson said yesterday he had not cited the Advisory Committee's report because it did not contain anything new.
"The idea that this is old data is neither here nor there: it is real data," he said. "The main problem with breast screening is that people don't know there is a down side. They mostly think it is going to save their lives."