Reducing the Risk of Breast Cancer


Part of an ongoing series devoted to promoting better health, this article offers strategies on reducing the risk of breast cancer. 


Karla never misses her yearly mammogram. She has three friends who have been diagnosed with breast cancer.

Heart disease is a more frequent killer, but most American women consider breast cancer a major risk – and with good reason. After lung cancer, it’s the second most common cause of cancer deaths.

Getting regular screening mammograms, as recommended, will not prevent cancer, but it is the best way  of detecting breast cancer at an early, treatable stage. Along with breast self examination, it is one of the most important things a woman can do to protect herself.

An American woman, if she lives to age 95, has a 1 in 8 chance of being diagnosed and a 1 in 35 chance of dying from breast cancer. Lowering these odds requires understanding of your risk factors and changing any that can be modified.

Estrogen has many benefits, but long-term exposure to this hormone is believed to increase the risk of breast cancer. Women who start menstruation early or end it late have estrogen exposure over an extended period. So do women who never become pregnant or become pregnant for the first time after age 35 (since pregnancy lowers estrogen levels temporarily). Estrogen levels are also lower while a woman is breast feeding.

After menopause, a women’s estrogen level drops, but those who take combination hormone replacement therapy (estrogen plus progesterone or progestin) have an increased risk of breast cancer that drops when the hormone therapy is discontinued.

Smoking: Studies suggest that women who start smoking at an early age are more vulnerable to breast cancer although a direct link between smoking and breast cancer has not been established.

Alcohol: In moderation, alcohol has been shown to offer some health benefits to the cardiovascular system, but one or two drinks a day is enough. The risk in terms of breast cancer is dose dependent: women who have two to five drinks a day are one and a half times more likely to get breast cancer than women who don’t drink at all.

Body Weight: Being overweight or obese (a BMI of 25 or higher) increases the risk of breast cancer. One reason may be that fat cells produce estrogen, which, in turn, makes hormone-sensitive cancers more likely to develop and grow.

Exercise is most beneficial in premenopausal women of normal weight. Data from the Women’s Health Initiative showed that even two and a half hours a week of brisk walking lowered breast cancer risk by 18 percent.

Radiation: Chest x-rays in young women before the age of 20 are not recommended unless there is a pressing medical need.

Adolescents who receive radiation therapy (particularly to the chest and neck) to treat Hodgkin’s disease or other cancers have an increased risk of breast cancer starting about 10 years after treatment and lasting for the rest of the person’s life.

Family History: You can’t do anything about your family history, but you should take extra precautions regarding risk factors and screening if an immediate member of your family has had breast cancer.

Genetic testing can reveal certain abnormalities in the BRCA1 or BRCA2 genes that greatly increase cancer risk. With an abnormal BRCA1 or BRCA2 gene, a women has an 80 percent chance of getting breast cancer at some time in her life. Some women with a very high genetic risk choose to have both breasts removed as a preventive measure – an extreme measure that often leads to anxiety, depression and other emotional problems.

For women at high risk because of heredity or because  of dense breast tissue, some experts are now calling for greater use of preventive therapy that includes medication.

Tamoxifen and raloxifene are currently approved in this country for prevention of breast cancer. Tamoxifen is more effective, cutting in half the risk of breast cancer for high-risk persons. It also has more serious potential side effects such as deep vein thrombosis and a higher risk of endometrial cancer.

Results from te Mammary Prevention (MAP.3) study showed that exemestane, an aromatase inhibitor, reduced the risk of invasive breast cancer by 65 percent. Adverse effects were no higher in the drug treatment than the placebo group. Only three years of follow-up have been reported, however.

It should be noted that only about 10 percent of American women fall into the high-risk category that might be considered for drug therapy. Others will benefit from regular screening plus healthy habits.  

Back to News Listing