Breast screening 'could do more harm than good': Women operated on needlessly, says report
By Jenny Hope
9th December 2011
Breast cancer screening may cause more harm than good, according to a study.
It says women are more likely to be harmed and have unnecessary surgery in the first decade of being screened.
The study concludes the ‘harms’ of screening, on average, largely offset the benefits in the first ten years. After that, the benefits increase, but by much less than predicted when routine screening was introduced.
The study is significant because it re-examines data from the 1986 Forrest report that led to the introduction of NHS screening.
The report used a formula to estimate costs and benefits, but did not include potential harms. It concluded screening would reduce deaths by one third, with few harms and low cost.
However, in the past decade there has been mounting evidence and controversy surrounding the true cost of screening to women in terms of ‘false positives’ and over-treatment of breast cancers that were never threatening. This has included needless breast removal.
In the latest study, James Raftery, professor of health technology assessment at the University of Southampton, and his colleague Maria Chorozoglou, brought the Forrest report up to date with an analysis of the outcome for 100,000 women aged 50 and over surviving up to 20 years after first being screened.
They looked at harms such as false positives, where women get abnormal results that turn out to be normal, and over-treatment, which may include surgery on harmless cancers that would never have caused symptoms or death during a patient’s lifetime.
The research published on the medical journal website bmj.com found that once harms were included, the benefits in terms of lives saved were only half original estimates.
In the first few years of screening, women were, on average, more likely to be harmed. The greatest benefit was for women aged 60 to 70, while older women may not live long enough to reap significant benefits.
Professor Raftery said: ‘At up to eight years, the harms generally outweigh the benefits, but at 20 years there are greater positive benefits.’
The vast majority of women undergoing surgery to remove a suspected tumour did not need the treatment.
‘There are lots of women who have had surgery who believe their lives were saved when in fact only around one in ten have had their life saved,’ said Professor Raftery.
He added: ‘There should be a fundamental overhaul of the screening programme – what’s the right time frame and how cost-effective is it?
‘We need trials to look at who is most likely to benefit from surgery and for measuring the levels and duration of the harms from surgery.’
A review of the NHS breast cancer screening programme has been announced by the national cancer director, Professor Sir Mike Richards.
Under the programme, which costs £96million a year in England, women are invited for three-yearly mammograms, or X-rays, between the ages of 50 and 70. The age limits are being extended to 47-73. Almost two million women are screened each year.
Researchers from the Nordic Cochrane Centre, who question the benefits of organised screening programmes, suggest the dramatic fall in breast cancer deaths in recent years is probably due to changes in risk factors and improved treatment.
They accused the heads of the NHS programme of sticking to beliefs from 25 years ago about the benefit of mammograms and supplying women with ‘astonishingly misleading’ statistics.
But Dr Caitlin Palframan of BreakthroughBreast Cancer said: ‘We believe breast screening is vital as it can detect breast cancer at the earliest possible stages.
The earlier breast cancer is picked up the better, as treatment options are more likely to be less aggressive and more successful.’
A spokesman for the Department of Health said it would look at the findings of the independent review, but added: ‘Our advice has not changed – we urge all women to go for breast screening when invited.
'The best available evidence shows screening saves lives by detecting cancers earlier than they would otherwise have been.’
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