MEDICAL MATTERS:Breastcheck, the national breast cancer screening programme, is a success with some 77 per cent of women invited for screening choosing to attend. But an underlying scepticism about breast screening persists; questions about its true impact on the reductions in deaths from the disease; and concerns about the information given to women outlining the pros and cons of being screened.
Now, what will be seen for many as the definitive study of the benefits of breast screening programmes has been published in The Lancet.
The report from an independent panel of experts, chaired by Prof Sir Michael Marmot of University College London, said that for every 10,000 UK women aged 50 years invited to screening for the next 20 years, 43 deaths from breast cancer would be prevented and 129 cases of breast cancer, invasive and non-invasive, would be over diagnosed. “That is one breast cancer death prevented for about every three over diagnosed cases identified and treated,” the panel concluded.
What is meant by over diagnosis? It is where screening identifies a tumour, which is consequently treated by surgery, and often radiotherapy and medication, but which would have remained undetected for the rest of the woman’s life without causing illness if it had not been detected by screening.
Commenting on the new research, Prof Mike Richards, UK national cancer director, said: “The key thing is that we communicate this new information to women so they can make an informed choice for themselves. NHS cancer screening programmes have already asked independent academics to develop new materials to give the facts in a clear, unbiased way. I hope to see them in use in the next few months.”
Marmot summed it up nicely when he added: “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 per cent 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.”
Retired breast radiologist Dr Patricia Fitzsimons has just completed a thesis at Dublin City University in which she makes a comparison between international screening programmes. One of her key findings is that screening programmes that use absolute statistics and inform women of the limitations of breast screening, have attendance rates approximately 10-15 per cent less than those that do not.
“Irish women are not currently making an informed choice and this goes against accepted norms of medical practice,” she says.
Fitzsimons makes an excellent suggestion when she says it is time for Breastcheck to lose its concerns about overall attendance rates in the age group it currently screens. Instead of focusing on age alone, why not change tack and screen women at high risk of breast cancer who are less likely to suffer an over diagnosis? Accounting for factors such as family history of breast cancer, obesity and alcohol intake – all risks for developing a breast malignancy – would help create a targeted screening approach.
It would be nice if Breast-check responded to The Lancet study by initiating a rewrite of its pre-screening information. Until it does so, it is failing its duty of care to the Irish women it invites for mammography.