Breast Cancer

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Our understanding of how to prevent and treat breast cancer has come a long way in the past 30 years, and as a result, there has been a steady decline in the mortality rate for breast cancer since 1992. Still, scientists are just beginning to unravel the complex interplay between risk factors and an individual's genes that stimulates the onset of breast cancer.

Breast cancer prevention primarily relies on reducing exposure to the known risk factors. This can be as simple as a daily walk or as aggressive as a prophylactic mastectomy. The level of prevention depends upon a person's absolute risk, family history, and level of concern. Each person needs to develop a strategy with her doctor or qualified medical professional, based upon the presence of any pre-existing conditions that may put her at higher risk for breast cancer. Factors to consider include a family history of breast cancer, a prior history of breast biopsy revealing LCIS or atypical hyperplasia, radiation treatments to the chest area before age 30, late or no history of live child births, early onset of menstruation, or late onset of menopause. See section on risk factors for more information.

For women who are at average risk and even those at high risk, breast cancer prevention typically focuses on fine-tuning lifestyle choices and may include any or all of the following:

  • Limiting alcohol consumption to one drink per day or less.
  • Maintaining a healthy weight.
  • Eating a low-fat diet.
  • Engaging in at least 30 minutes of regular physical activity most days of the week.
  • Avoiding long term—more than three to five years—postmenopausal hormone therapy that combines estrogen and progestin.
  • People whose family or personal history puts them at increased risk for breast cancer should discuss with their doctor or qualified health professional whether they need to pursue a more aggressive prevention strategy. Keep in mind that being identified as high risk doesn't mean that cancer is inevitable, but that you may need to be more vigilant about cancer prevention and risk-reducing measures. There is no consistent definition for "high risk." Often this term is used if someone has multiple risk factors, a very strong family history, or a breast cancer gene mutation. The risk-reducing options for women at very high risk for breast cancer include preventive mastectomy and preventive medications.

    Preventive mastectomy, also known as a prophylactic or risk-reducing mastectomy, involves removing one or both breasts to reduce the risk of developing breast cancer. Although preventive mastectomy can reduce the risk of breast cancer in high-risk women by about 90 percent, it does not eliminate the risk completely. Invariably some breast tissue, which extends across the chest wall from the collarbone down to the abdomen and into the armpit, remains after the procedure. Breast cancer can still develop in the small amount of remaining tissue.

    Individuals who are considering preventive mastectomy need to discuss how a mastectomy will affect the risk of developing breast cancer, the surgical procedure, psychological effects, and potential complications with their doctor. Prophylactic mastectomy and the subsequent breast reconstruction are major surgical procedures that run the risk of complications from anesthesia, infection, and bleeding. Preventive mastectomy should be considered in the context of each individual's unique risk factorsand level of concern.

    Preventive medications, also known as chemoprevention, involve the use of medications to reduce the risk of developing breast cancer. The drug tamoxifen, which blocks the action of the hormone estrogen from binding to the estrogen receptors in the breast, has been shown to reduce onset of breast cancer by about 50 percent in women. Tamoxifen is approved by the FDA for both premenopausal and postmenopausal women but carries a risk of adverse side effects including increased risk for blood clots and uterine cancer. A second option is raloxifene, a drug approved by the FDA for osteoporosis prevention and treatment but which has also been shown to reduce the risk of developing invasive breast cancer in postmenopausal women by about the same amount as tamoxifen. This drug does not have the same concern about uterine cancer as tamoxifen but can increase the risk of blood clots.

    No matter their risk, all women need to seek out the necessary screening to ensure that any breast cancer is found early on. Mammography, breast examination by a health professional, and breast familiarity and awareness are ways to detect breast cancer early. The American Cancer Society recommends that women begin annual screening mammograms at age 40, or five to 10 years earlier than the age at which the youngest affected first-degree relative was diagnosed. Clinical breast examinations should be conducted as part of a regular exam by a health expert at least every three years for women in their 20s. More recently in November 2009, the United States Preventive Services Task Force (USPSTF) released recommendations that women at average risk begin having routine screening mammograms at age 50 and continue every two years until age 75. The benefit of screening mammography is that it has led to a decrease in breast cancer deaths by 15-20 percent. There are some risks associated with screening. If an abnormality is detected on a mammogram, that may lead to a breast biopsy and false positives, which can result in increased anxiety. Women also need to be aware that a majority of breast cancers are diagnosed in women without a family history. To determine which screening interval is appropriate and when to begin screening, each woman should consult her doctor or health professional.

    Last reviewed on 3/28/10

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