30.10.12
4,000 cases of overdiagnosis from breast cancer screening
Breast cancer screening reduces deaths but also results in overdiagnosis, an independent panel has concluded.
The Breast Cancer Screening Review found that around 4,000 women a year will undergo unnecessary treatment for tumours which would otherwise have remained undetected and harmless.
Screening allows early detection of breast cancer, which offers the opportunity for earlier treatment and improved prognosis. The panel, set up by Cancer Research UK, found that women who attend the screening programme are at 20% less risk of dying from breast cancer.
The review recommends screening for 50-70 year old women should continue, as the mammography saves around 1,300 lives each year.
The Panel estimated that for 10,000 women invited to screening from age 50 for 20 years, about 681 cancers will be found, of which 129 will represent overdiagnosis, and 43 deaths from breast cancer will be prevented.
Professor Marmot, chair of the panel, said: “For each woman, the choice is clear. On the positive side, screening confers a reduction in the risk of mortality of breast cancer because of early detection and treatment.
“On the negative side, is the knowledge that she has perhaps a 1% chance of having a cancer diagnosed and treated that would never have caused problems if she had not been screened.
“Clear communication of these harms and benefits to women is essential, and the core of how a modern health system should function.”
A Lancet Editorial, published alongside the Review, concludes: “Overall, the benefits outweigh the harms…Women need to have full and complete access to this latest evidence in order to make an informed choice about breast cancer screening.”
National cancer director Sir Mike Richards said the Government was revising the leaflet that invites women for screening so that they can make an informed decision on whether to attend.
In a joint statement Breakthrough Breast Cancer, Breast Cancer Campaign and Breast Cancer Care said: “This is good news for women as they can now be assured that breast screening can be beneficial.”
The charities reiterated the importance of access to clear and balanced information for women invited to screening.
And on balance, Cancer Research UK recommends that women still attend the screening programme.
The review is at: www.thelancet.com/journals/lancet/article/PIIS0140-6736(12)61611-0/abstract
More on this story in the next edition of National Health Executive.
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