BREAST CANCER PREVENTION

There is no one single diet, food or supplement that can prevent or lower your risk of breast cancer. However, a healthy diet is still important to prevent against disease. Researchers have found that weight gain in middle life increases breast cancer risk.

Women can decrease their risk of breast cancer by engaging in regular exercise. Research has shown that in postmenopausal women, exercise and physical activity decreases the risk for breast cancer by changing oestrogen, insulin and insulin-like growth factor 1.

Exercise can also positively affect other risk factors such as obesity and insulin resistance. It has also been shown that post-diagnosis physical activity in women with breast cancer can improve the survival chance of the patients. Ideally, exercise at least 30 minutes per day, 5 days per week at a moderate to high intensity.

Obesity is associated with a 20% to 40% increased risk of breast cancer in post-menopausal women. In patients diagnosed with breast cancer, obesity is associated with a 33% increased risk of cancer recurrence and of death from any cause.

Additionally, gaining weight as an adult is associated with an increased risk of post-menopausal breast cancer. The risk increases by about 6% for each 5 kg increase in a woman’s weight.

However, having a higher BMI before menopause is associated with a decreased risk of premenopausal breast cancer. For each 5-unit increase in BMI, the risk of premenopausal breast cancer is decreased by about 7%. Importantly, obesity throughout life increases the risk of many other diseases such as heart disease and other cancers, leading to a higher rate of premature death.

It’s important to be aware of your family history with breast cancer, as a person’s risk of being diagnosed with breast cancer increases if they have a close relative who has had breast cancer. It’s estimated that 4% of Australian women have an increased risk of breast cancer due to family history, and only 1% are at high risk due to a strong family history.

Approximately 5-10% of breast cancers are due to a strong family history of genetic mutation such as BRCA1 or BRCA2. Some women with strong family histories receive genetic testing to see if they have one of these mutations.

Globally, alcohol is identified as a risk factor for a range of soft tissue cancers, including breast cancer [6]. It’s estimated that approximately 17 per cent of Australians drink alcohol at levels that put them at risk of harm over their lifetime. Alcohol is the most-established dietary risk factor, thought to be due to the increase of endogenous oestrogen levels it causes.

Women who drink one standard glass of alcohol (10g) a day have a 7 per cent higher risk of breast cancer than women who never drink alcohol. In Australia, it is estimated than almost 6 per cent of breast cancer cases each year are caused by alcohol consumption.

Evidence suggests there is no safe level of alcohol consumption in regard to an increased breast cancer risk, with a meta-analysis of 222 articles finding even light drinking (up to one drink per day) increases the risk of female breast cancer.

Several studies have shown there is an association between tobacco smoking and the risk of breast cancer. This association is observed particularly in women who smoke for a long time, or who smoke for a long time prior to their first pregnancy.

Tobacco smoke contains more than 5000 chemical compounds, including more than 70 that are known to be carcinogenic. Smoking has been found to be a major cause of heart disease, lung cancer and many other cancers, therefore not smoking is the best choice for your health.

Tamoxifen, a medication that is commonly used to treat breast cancer, also helps prevent breast cancer from occurring. It may be considered for women who are at a high risk of breast cancer due to their personal or family history.