Reducing the risk of breast cancer and breast cancer recurrence

Some substances or behaviours may lower your risk of developing breast cancer or reducing the risk of breast cancer coming back after treatment. The following is noteworthy research into ways to lower your risk.

Diet may help make breast tissue less dense. Research shows that women who limit the amount of meat and high-calorie foods (such as fat or oils) and eat large amounts of plant foods (such as vegetables and fruit) had lower density breast tissue. This was especially true in post-menopausal women and non-smokers (PLoS One, PMID 26208331). This is important because dense breasts have more connective tissue, glands and milk ducts than fatty tissue, which can make it harder to find cancer on a mammogram. Having dense breasts is an important breast cancer risk factor so lowering breast density by changing one’s diet may also reduce the risk of developing breast cancer. However, much longer follow-up is needed to find out if this is a way to reduce breast cancer risk.

Metformin(Glucophage) is a drug that helps control diabetes. Some studies suggest that women who take metformin have lower rates of breast cancer (Current Pharmacological Reports, PMID 26405648). A review of several studies found that metformin did not lower the risk for breast cancer, but it may improve survival in women diagnosed with the disease (Journal of Breast Cancer, PMID 26472977). A Canadian clinical trial is currently looking at the role of metformin in lowering the risk of breast cancer recurrence (NCT 01101438).

Anti-estrogen drugs such as tamoxifen (Nolvadex, Tamofen) or exemestane (Aromasin) may be offered to women who have a high risk of developing breast cancer to lower their chances of developing the disease. But many women choose not to take these drugs because they worry about their side effects and long-term effects. Researchers are trying to find ways to give these drugs so they cause fewer or less severe side effects. They are looking at lowering the dose of the drug or giving the drug for a short period of time with breaks in between (intermittent administration). Researchers hope that reducing the side effects might encourage more women at high risk for breast cancer to take these drugs (Seminars in Oncology, PMID 2690130).

Physical activity may improve survival after breast cancer. An analysis of physical activity reported by women found that brisk walking or other types of moderate exercise for 2.5 hours a week or more may lower the chance of dying from breast cancer by as much as 32%. More research is needed to understand how physical activity can help improve survival (European Journal of Cancer, PMID 27529756).

Find out more about research in reducing the risk of cancer.