Lower your risk of breast cancer

Your risk of breast cancer increases as you age.

After menopause, the hormone oestrogen is produced in fat tissue rather than in the ovaries. So, maintaining a healthy body weight can help limit the amount of oestrogen your body produces.

Regular physical activity can reduce your risk of developing breast cancer, and decrease the risk of breast cancer coming back in those who have been diagnosed.

Regular exercise can help balance hormones and other natural processes in your body, such as how it controls blood sugar and supports cell growth. These are linked to breast cancer risk.

Drinking alcohol can slightly increase the risk of developing breast cancer. The more alcohol you drink, the greater the potential risk.

Choosing to drink less, or not drink at all, can help to lower your breast cancer risk. It can also provide other benefits like better sleep, energy, and heart health.

Small changes can make a difference, like having alcohol-free days or choosing lower-alcohol drinks. We encourage everyone to weigh decisions up against your own habits and lifestyle choices.

Alcohol also increases the risk of several other cancers. For more guidance, read the Cancer Society's position on alcohol and cancer.

Menopausal hormone therapy (MHT), also called hormone replacement therapy or HRT, can be an effective treatment for menopausal symptoms. Some types are linked to an increased risk of breast cancer.

The level of risk depends on factors including the type of MHT and how long it’s used. MHT containing both oestrogen and progestogen is associated with a greater increase in risk while you are using it, and for two to five years after you stop. Oestrogen-only MHT has little or no change in breast cancer risk.

If you’re considering MHT for menopausal symptoms, talk to a doctor about the risks and benefits. It’s recommended you use the lowest dose that controls your symptoms, for the shortest possible time.

Current or recent use of some hormonal contraceptives is associated with a small increase in breast cancer risk. This includes the combined oral contraceptive pill (that contains oestrogen and progestogen). The risk increases the longer the pills are used.

Oral contraceptives are considered relatively safe for women under the age of 40 who are not already at high risk of breast cancer.

Depo Provera, an injectable progesterone, has been shown to slightly increase breast cancer risk, but this stops after you stop taking it. Hormonal IUDs, such as Mirena, may also slightly increase breast cancer risk.

Hormonal contraception also has benefits, including preventing pregnancy and lowering the risk of ovarian and endometrial cancers.

If you are concerned, talk to a doctor about the benefits and risks of the different options. Your personal risk will depend on factors like your age, health and family history.

When and whether you have children can influence the risk of developing breast cancer. Having children earlier in life is linked to a slightly lower lifetime risk than having children later or not giving birth.

For a few years after giving birth, breast cancer risk increases slightly before becoming lower over the longer term.

Breastfeeding is associated with a lower risk, and the benefit increases with the total time spent breastfeeding.

Decisions about whether or when to have children are personal and shaped by many circumstances. They shouldn’t be made on breast cancer risk alone. Talk to a GP if you are concerned about your individual risk.

Disrupted sleep patterns (also called disrupted circadian rhythms) has been linked to higher risk of breast cancer in women. It is not fully understood how sleep impacts breast cancer, but it may be linked to changes in hormone levels, or changes in the immune system. Sleep can be disrupted by shift work, not getting enough sleep or being exposed to light at night.

This is a small increase in risk. If you’re a shift worker, or have disrupted sleep for another reason, talk to a GP about your overall risk.

Sources

1. The incidence of breast cancer among female flight attendants: an updated meta-analysis Journal of Travel Medicine, November 2016, https://doi.org/10.1093/jtm/taw055
2. Night Shift Work and Risk of Breast Cancer Curr Environ Health Rep. 2017 Sep;4(3):325-339. doi: 10.1007/s40572-017-0155-y.