Our scientists launched the first pilot trial of breast cancer prevention at the Royal Marsden Hospital in 1986. They found that patients treated with tamoxifen were less likely to develop a second breast cancer.

In the 1990s, this trial developed into a full scale prevention study, the International Breast Cancer Intervention Study (IBIS I). The trial showed that the drug can help to cut the risk of breast cancer in women at high risk of the disease.

Cancer Research UK is now funding IBIS II, which is recruiting thousands of post-menopausal women. The trial is testing whether the drug anastrozole can prevent breast cancer with fewer side effects in women at greater risk of the disease. There is more information on the IBIS II website.

Watch our video to find out more from the IBIS II scientists and trial participants.

In 2003, the Million Women Study – funded by Cancer Research UK – showed that hormone replacement therapy (HRT) could increase the risk of breast cancer. Overall, researchers think that HRT use has caused about 20,000 breast cancer cases in the UK over the last decade.

Results from EPIC, the largest ever study of lifestyle and cancer, showed that exercise can reduce the risk of breast cancer, as well as cutting the risk of other types of cancer. And the study has also shown that being overweight or obese after the menopause can increase the risk of the disease.

Reduce your risk

Learn more about the symptoms of breast cancer and how you can reduce your risk of developing the disease by downloading our breast cancer leaflet (PDF, 310KB).