Benefits of breast cancer screening questionedMay cause more harm than good
Breast cancer screening may be causing more harm than good, according to a new study.
Screening was introduced to the UK after the publication of the The Forrest report in 1986. But the report did not include the potential "harms" of breast cancer screening, researchers at the University of Southampton said.
Screening sometimes leads to false positive results, where an abnormal result turns out to be normal after further investigation.
On other occasions a patient may be given treatment - including surgery - for a cancer that would never have caused symptoms or death during their life. This may be because the cancer grows so slowly that the patient dies of other causes before any symptoms appear, or the cancer remains dormant or regresses.
The benefits of screening are measured in "quality of years" (QALYs), a combined measure which takes into account the extra years and quality of life the patient gains due to screening.
The original Forrest report estimated that patients gained more than 3,000 QUALYs over a 20 year period for every 100,000 screened.
But after adjusting for false positive results and unnecessary surgery, the new study found that the QUALYs figure is around 1,500 after 20 years, around half of what was originally calculated.
Up to the first eight years of breast cancer screening, the harms generally outweigh the benefits, but after this there is an increasing benefit. However, the benefits of screening are much less than predicted by the Forrest report, the researchers said.
The researchers called for improved ways of identifying women who would be most likely to benefit from surgery, and added that the problems of overdiagnosis and overtreatment should be better explained to women before screening.
This article was published on Fri 9 December 2011
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