Breast cancer screening debate

I am very aware of the debate that has been ongoing among experts about the effectiveness of breast screening and  how this can cause confusion and anxiety for some women. Last year a Danish study found that breast cancer screening programmes did not reduce cancer death rates and while mammograms can spot dangerous tumours, they might also detect lumps that are essentially harmless, exposing some women to undue anxiety and surgery. However, the latest study now suggests that the benefits of breast cancer screening  outweigh any downsides, by saving the lives of two women for every one who may have unnecessary treatment. The study by experts from the Wolfson Institute of Preventive Medicine at Barts and the London School of Medicine and Dentistry appears in the Journal of Medical Screening. It focused on data from 80,000 women from the age of 50, and looked at data from Sweden and England before and after the introduction of screening. The research estimated that 5.7 breast cancer deaths were prevented for every 1,000 women screened over a 20-year period At the same time, 2.3 women per 1,000 were told they had a lump but it was not clear if it was an aggressive form of cancer that needed to be treated. Put another way, for every 28 cases diagnosed, 2.5 lives were saved and one case was over-diagnosed.

The authors of this latest study say the benefits of breast screening are clear. “Analysis shows a substantial and significant reduction in breast cancer deaths in association with mammographic screening,” they said.

While, there is a risk of over-diagnosis, and possible subsequent over-treatment associated with any screening programme, this latest independent study shows that the risk of over-diagnosis is very much lower than some other recent estimates have claimed, and that the benefits far outweigh the risks. What we need to remember is that detecting cancers earlier generally means improved survival and because it is detecting cancers at the early stages can in many cases also mean less invasive /aggressive treatments. Breast cancer is localised to the breast at the beginning, not a systemic disease. It is a progressive disease, which can be arrested through early detection and treatment.

I feel the debate will still continue though, and while I am convinced of the benefits of breast screening, I still advocate for women to make up their own minds about the risk/benefit ratio. Yes, there is a chance of overtreatment – no screening tool is 100% fool-proof – but weighing up all the pros and cons,  I would still be prepared to take that risk.

In Ireland BreastCheck, a Government-funded programme, provides breast screening and invites women aged 50 to 64 for a free mammogram on an area-by-area basis every two years. More information at
You might also find it helpful to read this EDI guide to screening