Breast Cancer Prevention

Preventing & Detecting Breast Cancer Early

Breast cancer accounts for about 30% of all new cancer diagnoses in women. While it can also occur in men, this is rare. The most common form of it is invasive ductal carcinoma. This type of breast cancer starts in the milk ducts and spreads to other breast tissues and areas outside the breast.

The most common sign of breast cancer is a lump or mass in the breast. Other signs and symptoms can include nipple discharge, swelling, nipple tenderness, skin changes on the breast or nipple, and changes in size, shape or appearance of the breast or nipple. Fortunately, routine screening tests find many breast cancers early in their most treatable stages, before symptoms even appear. There are even some preventive strategies available for certain women. All of this has contributed to the death rate for breast cancer falling over time. However, breast cancer still claims the lives of more women than any other cancer besides lung cancer. This continues to make early detection and prevention of breast cancer an important part of women’s health.

What are the risk factors for breast cancer?

Health experts know a number of factors increase the risk of developing breast cancer. Keep in mind, not all people with these risk factors will get breast cancer. And breast cancer can also affect women with no risk factors at all.

Risk factors for breast cancer include:

• Age — the risk gets higher with age, especially after 50
• Caucasian race
• Dense breast tissue and other breast conditions, such as fibroadenoma; dense breast tissue can also make it more difficult to read mammograms
• DES (diethylstilbestrol) exposure
• Early menstruation before age 12 or late menopause after age 55
• Family or personal history of breast cancer
• Genetics — about 5 to 10% of breast cancers are related to mutations in genes, such as BRCA1 and BRCA2
• Previous chest radiation therapy

Lifestyle factors, such as being overweight or obese, not exercising, and consuming alcohol can also increase the risk. Carrying extra weight after menopause is an important risk factor for older women. Fatty tissue produces estrogen and is the main source of estrogen after the ovaries stop working. Higher estrogen levels after menopause can increase the risk of breast cancer. Tumors that grow more in the presence of estrogen—or are hormone-receptor positive—are more common in postmenopausal women. High estrogen levels after menopause also make it more likely that the cancer will return.

Reducing your risk of breast cancer

Like any other cancer, the main strategy for reducing your risk of breast cancer is to change risk factors that you can control. For breast cancer, this focuses on lifestyle risk factors for most women. You may be able to lower your risk of breast cancer by maintaining a healthy body weight, getting regular exercise, and drinking alcohol only in moderation. For women, alcohol consumption should not exceed one drink per day.

Because many risk factors for breast cancer are not controllable, breast cancer can still occur. And women with no risk factors can still get the disease, making it impossible to reduce the risk for these women. However, there is another group of women who are at very high risk. It includes women with a strong family history of breast cancer (such as a mother or maternal aunt with the disease) and those with genetic testing positive for a gene mutation, such as BRCA1 or BRCA2. For these women, there are specific prevention strategies available, including:

• Chemoprevention, which uses drugs to try to prevent breast cancer from developing. This includes tamoxifen (Nolvadex) and raloxifene (Evista). These drugs block the effect of estrogen on breast tissue, which can decrease the risk of breast cancer in some women. Other drugs, called aromatase inhibitors, may also be effective for chemoprevention. These drugs lower estrogen levels by blocking an enzyme. They include anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara). While aromatase inhibitors do not currently have FDA approval for this purpose, many cancer specialists offer them as alternatives for certain women. Promising results from large studies are the basis for this option.
• Mastectomy, which is surgery to remove the breasts. In women without breast cancer, this procedure is a prophylactic mastectomy. It can reduce the risk of breast cancer by about 97%. However, there is still a small chance of getting breast cancer because some breast tissue cells can remain after surgery. Women who have breast cancer in one breast may also choose to remove the other breast in an effort to prevent breast cancer from developing in it. This is a contralateral prophylactic mastectomy.
• Oophorectomy, which is surgery to remove the ovaries. Before menopause, the ovaries are the main source of estrogen, and estrogen fuels many breast cancers in women with BRCA1 or BRCA2 mutations. Removing the ovaries can cut the risk of breast cancer in half for these women. Very high-risk women may choose to combine this surgery with a prophylactic double mastectomy.

Every woman should discuss her breast cancer risk with her doctor because knowledge is power. Knowing your risk can help you make informed decisions about your lifestyle. It can also tell you if you need additional screening or if you should consider genetic testing.

Is Genetic Testing Right for You?

Early detection of breast cancer

Since risk reduction is not 100% effective, early detection offers the best chance of successfully treating breast cancer. Screening exams are the main tools for early detection. They look for breast cancer before you have symptoms, often before you can even feel a lump. The two primary breast cancer screening exams for women at average risk are breast exams and mammograms:

• Clinical breast exam is a physical exam your doctor performs during a regular checkup. Your doctor will visually check your breasts and feel all areas of your breast and underarm to check for lumps and changes in texture. Your doctor may ask you to raise your arms above your head or change positions during the exam.
• Mammograms use low-dose X-rays to produce an image of your breast. Screening mammograms are the most effective tool for finding breast cancer early. Women can start yearly screening mammograms at age 40, but may not need to until later. Your doctor is the best source for deciding when to start.

For some women, these two screening tests are not enough to reliably check for breast cancer. This includes women with a lifetime risk higher than 20% and those with BRCA1 or BRCA2 mutations. Your doctor will use a risk evaluation tool that takes risk factors into account to determine your lifetime risk. For these high-risk women, mammograms should start before age 40. They should also have additional screening with MRI (magnetic resonance imaging).

If your screening exams reveal a suspicious area, your doctor will recommend diagnostic testing to confirm or rule out breast cancer. These tests may include:

• Diagnostic mammogram, which takes many close images of the area of interest
• MRI
• Breast ultrasound, which uses painless sound waves to create pictures of breast structures

Breast Biopsy

The results of these additional imaging exams will guide your doctor’s recommendations. If further examination shows the area is benign (not cancer), you may not need to do anything else. Your doctor may only suggest more frequent follow-up. If your doctor is still concerned, a biopsy may be the next step. A biopsy removes a small tissue sample to check it for cancer. It is the only way to tell with absolute certainty whether an area is cancerous or not.

If a biopsy shows cancer is present, your doctor will need a complete diagnosis, including the stage, grade, and receptor status of the tumor. The stage at the time of diagnosis is important for your prognosis and treatment options. There are five stages for breast cancer numbered 0, I, II, III, IV and V. Fortunately, about 61% of breast cancers remain confined to the breast at diagnosis. This corresponds to stage I or early stage II. These early stages are typically the most treatable forms of breast cancer.

Learn More