Some of the factors associated with breast cancer – being a woman, age, and genetics – can’t be changed. Other factors – being overweight, lack of exercise, eating unhealthy food – can be changed by making the right choices.
Researchers prioritized the following breast cancer prevention strategies:
Exercise regularly and maintain a healthy weight throughout life: Exercise and being at a healthy weight can reduce the risk of breast and other cancers. Research has shown that gaining weight after age 18 is linked to a higher risk of postmenopausal breast cancer that is directly related to the amount of weight gained. This higher risk is because fat cells make estrogen; extra fat cells mean more estrogen in the body, and estrogen can make hormone-receptor-positive breast cancers develop and grow.
At the same time, overweight postmenopausal women who lost 22 or more pounds and kept it off reduced their breast cancer risk by more than 50% compared to women who didn’t lose weight.
Regular exercise reduces breast cancer risk for both pre- and postmenopausal women. The American Cancer Society and many doctors recommend women exercise 4 to 5 hours per week at a moderate intensity level. Brisk walking is considered moderate intensity exercise.
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Limit alcohol: Research suggests that drinking more increases breast cancer risk. Each 10-gram-per-day increase in alcohol consumption leads to a 7% to 10% increase in breast cancer risk (an average drink has about 14 grams of alcohol). Even light drinking can increase risk.
Still, many people believe the heart benefits of drinking alcohol, especially red wine, outweigh any breast cancer risks. But it’s important to know that there are other ways to keep your heart healthy besides drinking alcohol. Women who are concerned about breast cancer risk may want to limit alcohol or avoid it completely.
The researchers reported that women who most closely stuck to the American Cancer Society guidelines for weight, diet, drinking alcohol, and exercise had a 22% lower risk of breast cancer compared to women who strayed the farthest from the guidelines.
Consider preventive medicine: The U.S. Preventive Services Task Force (USPSTF) and the American Society of Clinical Oncology (ASCO) released new guidelines on using hormonal therapy medicines to reduce risk in women with a high risk of breast cancer who haven’t been diagnosed.
The USPSTF guidelines say that doctors should offer the medicines tamoxifen and raloxifene to women aged 35 and older with a high risk of breast cancer who have never been diagnosed to reduce their risk. The task force didn’t recommend that women at average or low risk of breast cancer be offered these medicines. Hot flashes and night sweats are side effects, though they’re more common with tamoxifen. The medicines can sometimes cause dangerous blood clots in rare cases. This complication is more common with tamoxifen.
While studies show the effectiveness of these medicines, other research has found that they’re not widely prescribed by doctors or taken by women at high risk of breast cancer because of concerns about side effects.
The study was published in the May/June 2014 issue of CA: A Cancer Journal for Clinicians. It's available here: “Priorities for the primary prevention of breast cancer.”