A risk stratified approach could improve the cost effectiveness of the UK’s breast screening programme and reduce the “cost” of overdiagnosis to women, a study has found.
Not offering breast cancer screening to women at lower risk would still maintain a reduction in breast cancer deaths, said the authors of a modelling study published in JAMA Oncology.1 However, the charity Breast Cancer Now, while supporting a risk based approach, found it “extremely concerning” that this particular model would see more women die overall.
The screening programme in the UK invites all women aged 50 to 69 for digital mammography every three years. The risk of developing breast cancer varies, and the current “one size fits all” approach does not take individual variation into account, the study authors said.
Nora Pashayan, lead author, from the department of applied health research at University College London, said, “The take-up of breast screening is currently around 72%. If we maintain this take-up but in a way that women who would benefit more from screening attend and women who would be more harmed from screening are spared, then the cost effectiveness and benefit-to-harm balance of the NHSBSP [breast screening programme] could be improved.”
The NHS says that the screening programme saves about one life from breast cancer in every 200 women who take part, adding up to about 1300 lives saved each year in the UK.2 However, it also estimates that about three in every 200 women screened every three years aged 50 to 70 are found to have a cancer that would never have been diagnosed without mammography and would never have become life threatening. This adds up to about 4000 women each year in the UK who are offered treatment that they did not need.
In the Cancer Research UK funded study the researchers simulated three hypothetical cohorts of women, aged 50 and free of cancer, being followed up over 35 years. Each cohort consisted of 364 500 women—the 2009 population of women aged 50 in England and Wales. The first group received no screening; the second received a mammography at age 50 and for every three years thereafter, simulating the NHSBSP; and in the third cohort a risk estimation was carried out, and only those with a risk score greater than the threshold (low) risk were offered screening every three years from 50 to 69.
In the risk stratified group, among the women who were not screened the researchers found 27% fewer overdiagnoses, 3% fewer breast cancer deaths avoided, and the cost to the NHS reduced by £20 000. In the high risk 70% they found 71% fewer overdiagnoses, 10% fewer breast cancer deaths avoided, and an NHS cost lower by £538 000.
Delyth Morgan, chief executive of Breast Cancer Now, said that the breast cancer screening programme is “absolutely critical” to early diagnosis in this country and called for the development of more accurate risk prediction tools.
She said, “While we remain hopeful that ‘risk stratified screening’ will offer another significant step forward in the early detection and prevention of breast cancer, it’s extremely concerning that this particular model would see more women die from their disease as a result.
“Using an even more personalised approach could help detect more cases earlier, while enabling those at particularly low risk to avoid unnecessary screening—but, to stop more women dying from breast cancer, we first need to develop accurate risk prediction tools and find ways to support women to reduce their risk of the disease.”
- N PashayanS MorrisFJ Gilbert. Cost-effectiveness and benefit-to-harm ratio of risk-stratified screening for breast cancer: a life-table model. JAMA Oncol2018. 10.1001/jamaoncol.2018.1901.
- NHS Choices. Breast cancer screening: benefits and risks. 2018. https://www.nhs.uk/conditions/breast-cancer-screening/why-its-offered/.
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