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Breast Screening Atypia: Observational Analysis of Subsequent Development of Cancer using Sloane UK database (Sloane Atypia)

Cancer cells

Sloane Atypia

In England we offer breast screening every three years to women aged 50 to 70 years. In 2018/19 the NHS breast cancer screening programme screened over two million women. A potential abnormality was identified in nearly 85,000, who were recalled for further tests. Cancer is detected in nearly 20,000 of these women but a small proportion have types of abnormality that are not cancer. These are called atypical epithelial proliferations, or atypia. Whilst these women do not have cancer, some of them may be 4 times more likely to develop cancer in the future than women without atypia. However, we currently do not know what the true risk is for these women. We do not know how many of these women will develop cancer, or how long it will take and the types of cancer if it does develop. Because of this uncertainty there are no national guidelines and therefore variation in care across the UK. Some screening centres offer women with atypia, regardless of type, mammography tests, every year for 5 years. Other centres continue to offer routine 3-yearly mammograms. We do not know what is the best care for women, as mammography, and the test offered, can also cause discomfort and anxiety.

We propose a research project using data from women in England who have had atypia in the last 17 years. We want to find out:

1) how many women develop cancer;

2) at what time they develop cancer;

3) the type and severity of cancer.

We also want to investigate to what degree this information differs depending on the type of atypia.


Why is this important?

This new knowledge will help to improve the care offered to women with atypia. We believe this is possible by offering more mammography test to women who need them most and avoiding the harm from screening to those women who do not need more tests. We will publish our results and use them to advise the NHS Breast Screening Programme about what should be recommended for women diagnosed with atypia. We will also report results to the breast screening centres and provide lay summaries for women and the public. What we do at the moment is not based on research evidence, so our findings could have a large influence on breast screening practice.