Definition
Breast cancer is a disease in which cancer cells grow in the breast tissue.
Cancer occurs when cells in the body divide without control or order. If cells keep dividing uncontrollably, a mass of tissue forms. This is called a growth or tumor. The term cancer refers to malignant tumors. They can invade nearby tissue and spread to other parts of the body.
Although most people think of breast cancer as affecting women, men can develop breast cancer as well. Breast cancer in men can be more aggressive.
Causes
The cause of breast cancer is not known. Research shows that certain risk factors are associated with the disease.
Risk Factors
Factors that increase your risk for breast cancer include:
- Sex: female, although men can also get breast cancer
- Age: 50 or older
- Personal history of breast cancer
- Family members with breast cancer
- Changes in breast tissue, such as atypical ductal hyperplasia, radial scar formation, and lobular carcinoma in situ (LCIS)
- Changes in certain genes (BRCA1, BRCA2, and others)
- Race: Caucasian
- Increased exposure to estrogen over a lifetime through:
- Early onset of menstruation
- Late onset of menopause
- No childbearing or late childbearing
- Absence of breast-feeding
- Hormone replacement therapy
- Tobacco use
- Increased breast density (more lobular and ductal tissue and less fatty tissue)
- Radiation therapy before the age of 30 years old
- Overuse of alcohol
Note: Studies show that most women with known risk factors do not get breast cancer. Many women who get breast cancer have none of the risk factors listed above except age.
Symptoms
When breast cancer first develops, there may be no symptoms at all. But as the cancer grows, it can cause the following changes:
- A lump or thickening in or near the breast or in the underarm area or in the neck
- A change in the size or shape of the breast
- Nipple discharge or tenderness, or the nipple pulled back (inverted) into the breast
- Ridges or pitting of the breast skin (like the skin of an orange)
- A change in the way the skin of the breast, areola, or nipple looks or feels (for example, warm, swollen, red, or scaly)
Note: These symptoms may also be caused by other, less serious health conditions. Anyone experiencing these should see a doctor.
Diagnosis
The doctor will ask about your symptoms and medical history. A physical exam will be done. It will include a breast exam.
- Your doctor may need pictures of structures inside your body. This can be done with:
- Mammography
- Ultrasonography
- Computed tomography (CT) scan
- Positron emission tomography (PET)/CT scan
- Your doctor may need to test your breast tissue. This can be done with different biopsy types, including:
- Fine-needle aspiration—removal of fluid and/or cells from a breast lump using a thin needle
- Needle biopsy—removal of tissue with a needle from an area that looks unusual on a mammogram but cannot be felt
- Surgical biopsy:
- Incisional biopsy—cutting out a sample of a lump or suspicious area
- Excisional biopsy—cutting out all of a lump or suspicious area and an area of healthy tissue around the edges
- Your doctor may need to test your tissue and bodily fluids. This can be done with: .
- Tissue evaluation—breast cancer tissue is tested for estrogen and progesterone receptors, as well as the presence of HER2/neu. These are used to help plan therapy
- Genetic testing—blood is evaluated for specific gene mutations in certain patients
Treatment
After breast cancer is found, staging tests are done. This will help to find out if the cancer has spread and, if so, to what extent.
Treatments include:
Surgery
- Lumpectomy—removal of the breast cancer and some normal tissue around it. Often, some of the lymph nodes under the arm are also removed. This may also be called tylectomy or quadrantectomy.
- Segmentectomy—removal of the cancer and a larger area of normal breast tissue around it.
- Simple mastectomy—removal of the breast, or as much of the breast as possible. The surgeon will try not to remove lymph nodes.
- Radical mastectomy—removal of the breast, both chest muscles, the lymph nodes under the arm, and some additional fat and skin. This procedure is only considered in rare cases. It is done if the cancer has spread to the chest muscles. This procedure is rarely done in the US at this time.
- Modified radical mastectomy—removal of the whole breast, the lymph nodes under the arm and, often, the lining over the chest muscles.
- Sentinel lymph node biopsy—a small amount of blue dye and/or a radioactive tracer is placed in the area where the tumor was located. The lymph nodes that pick up the substance are removed. Those remaining lymph nodes should be removed if any sentinel nodes contain cancer. This method is usually done in women who do not have lymph nodes that can be felt in the armpit.
- Axillary lymph node dissection—Removal of the lymph nodes under the arm. This is done to help determine whether cancer cells have entered the lymphatic system.
Radiation Therapy
Radiation therapy is the use of radiation to kill cancer cells and shrink tumors. Two main types of radiation may be used:
- External radiation therapy—radiation directed at the breast from a source outside the body
- Internal radiation therapy—radioactive materials placed into the breast in or near the cancer cells
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. It may be given in many forms including pill, injection, or via a catheter. The drugs enter the bloodstream. They travel through the body killing mostly cancer cells. Some healthy cells are killed as well.
Biologic Therapy
Biologic therapy is the use of medicines or substances made by the body. They can increase or restore the body’s natural defenses against cancer. It is also called biologic response modifier (BRM) therapy.
Hormonal Therapy
Hormonal therapy is designed to take advantage of the fact that many breast cancers are estrogen sensitive. Estrogen binds to the estrogen-sensitive cells and stimulates them to grow and divide. Anti-estrogen drugs prevent the binding of estrogen. This stops the cells from growing and prevents or delays breast cancer from returning.
Prevention
Finding breast cancer early and treating it is the best way to prevent death from the disease. Breast cancer does not cause symptoms in the early stages. It is important to have screening exams and tests. These steps can help to find the cancer before symptoms appear. The following recommendations are for women with no symptoms who are not high risk for breast cancer:
- Mammograms:
- Age 40-49—Recommendations vary from waiting until age 50 to having the screening every 1-2 years.
- Age 50-74—Ranges from every year to every two years
- Clinical breast exam:
- Age 20-39—ranges from every year to every three years
- Age 40 and older—every year
- Breast self-exam is optional for those age 20 and older. Talk to your doctor about the risks and benefits.
If you have an increased risk of breast cancer, you may need to start having mammograms earlier. You and your doctor can decide on the best screening schedule for you.
If you are at very high risk for breast cancer, surgery to remove your breasts before you get cancer (called prophylactic mastectomy) may be an option.