Breast cancer is one of the most common cancers in U.S. women (1 in 8 women).
Obesity, lifestyle (inactivity, alcohol use, smoking, night shift work), and radiation exposure to the chest also increase risk.
Your genes, hormones, lifestyle, and environment work together to lead to breast cancer, but we don’t know exactly how. We know that estrogen (the major female hormone) and progestin (a synthetic form of progesterone, another female hormone) can cause breast tissue to grow faster than normal. While long-term use of estrogen/progestins during menopause has been associated with higher breast cancer risk, contraceptive use in pre-menopausal women with low or moderate dose estrogen has not. Certain genes (such as BRCA1 or BRCA2) greatly increase breast cancer risk.
The most common way to find breast cancer is through a breast exam or mammogram (x-ray). High risk women may also need screening MRI (magnetic resonance imaging) scans, which are more sensitive than a mammogram.
Not all lumps are cancer. If you find a lump, or a lump that has changed in size or consistency, your doctor may order a variety of tests. These tests can include:
Treatment for breast cancer depends on the type and the stage of the cancer. Typical treatments include surgery, radiation therapy, chemotherapy, anti-estrogen hormone therapy, ovarian suppression therapy, targeted monoclonal antibody therapy, or a combination of these. Anti-estrogen hormone therapy includes selective estrogen receptor modulators (tamoxifen/raloxifene) which blocks the effect of female hormones on the cancer and aromatase inhibitors (anastrozole, letrozole, or examestane) which prevent the body from making female hormones.
If you are at high risk for developing breast cancer, tamoxifen or raloxifene can also be taken to prevent the disease. Your doctor will work with you to determine the best treatment option for you.
Lifestyle changes, such as regular exercise, eating fruits/vegetables, and avoiding excess alcohol, daily red meat, or any tobacco smoke exposure, may be helpful in preventing breast cancer. Breastfeeding for at least six months, planning your first child before age 30, limiting night shift work, and avoiding/limiting menopausal hormone therapy may also be protective.
Most breast cancers in the United States are diagnosed after an abnormal screening study. You should have a screening mammogram every year or two, starting no later than age 50. Many health professional organizations recommend starting mammograms at age 40, but individualized decisions are also recommended.
If you are at high risk for breast cancer, you should get an annual mammogram and breast MRIs, spaced six months apart, at age 40. Talk with your provider about other screening tests, medications to prevent breast cancer, or genetic testing.
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