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Women confused about breast cancer 'overdiagnosis'

Many women do not fully understand the risks of 'overdiagnosis' in the NHS Breast Cancer Screening programme, researchers have found. 

Overdiagnosis is the risk that screening could pick up cancers that would not have gone on to cause any harm. 

It happens because some breast cancers grow so slowly that it would take more than a lifetime for them to threaten a woman's health. 

Information about overdiagnosis has only been included in NHS breast screening invitations since late last year. 

In a survey of around 2,200 women, Cancer Research UK found that 64% believed they fully understood the information provided about overdiagnosis. 

And 7% of women would be less likely to attend screening after receiving information about overdiagnosis. 

Study author Dr Jo Waller, a researcher at the Health Behaviour Research Centre at University College London said: “While there is clearly room for improvement, the information leaflet does appear to help some women make a decision about whether or not to have breast screening.

“But the study found that many women still struggle to understand the balance of benefits and harms linked to breast screening, so we need to find better ways to communicate the risks as well as the benefits.” 

For every life that is saved through screening, researchers estimate that three women will be overdiagnosed with breast cancer. 

Sara Hiom, Cancer Research UK's director of early diagnosis, said: “We think it's vitally important for women to have clear information about breast screening, the balance of benefits and harms and the fact that they could be diagnosed with and treated for a cancer that might not have caused them harm. 

“The concept of overdiagnosis is still very new for a lot of women because it has only been included in the NHS leaflets for a year. We hope that over time, people's understanding of this concept will increase as more and more women receive information explaining this risk of screening.” 


Waller, J et al. A survey study of women's responses to information about overdiagnosis in breast cancer screening in Britain (2014) British Journal of Cancer. doi: 10.1038/bjc.2014.482