Breast cancer is a disease in which cancer cells grow in the breast tissue. It is the most common cancer in women in the United States. The normal breast consists of glandular tissue called lobes. These lobes are sectioned off into lobules, which produce milk. Milk is carried to from the lobules to the nipple by small ducts. All this tissue is surrounded by fatty and connective tissue, as well as blood and lymph vessels.
Types of breast cancer found in women are:
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Cancer occurs when cells in the body divide without control or order. Eventually these uncontrolled cells form a growth or tumor. The term cancer refers to malignant growths. These growths can invade nearby tissues including the lymph nodes. Cancer that has invaded the lymph nodes can then spread to other parts of the body. The lymph nodes associated with breast cancer are in the armpit, above the collarbone, and in the chest.
It is not clear exactly what causes these problems in the cells, but is probably a combination of genetics and environment.
Breast cancer is more common in Caucasian women, aged 50 years and older. Other factors that may increase your chance of breast cancer include:
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.
When breast cancer first develops, there may be no symptoms at all. As the cancer grows, it can cause the following changes:
Note: These symptoms may also be caused by other, less serious health conditions. Anyone experiencing these should see a doctor.
The doctor will ask about your symptoms and medical history. A physical exam will be done. It will include a breast exam and blood tests.
Imaging tests can help diagnose and evaluate the extent of the cancer. Imaging tests include:
Your doctor may need to test your breast tissue and adjacent lymph nodes. A sample will be removed and sent to a lab to look for cancer cells. This can be done with different biopsy types, including:
If cancer is present, your doctor may order tests to learn about the type of cancer. These may include:
The physical exam combined with all of your test results, will help to determine the stage of cancer you have. Staging is used to guide your treatment plan. Like other cancers, breast cancer is staged from 0-IV. Stage 0 is a very localized cancer, while stage IV indicates a spread to other parts of the body.
Cancer treatment varies depending on the stage and type of cancer. A combination of therapies is most effective. For example, radiation may be used before surgery to shrink the tumor or after to make sure all the cancer has been removed.
Treatment options include:
The goal of surgery is to remove the tumors and any affected tissue.
Radiation therapy is the use of radiation to kill cancer cells and shrink tumors. The main types of radiation include:
Chemotherapy is the use of drugs to kill cancer cells. It may be given in many forms including pill, injection, or IV. The drugs enter the bloodstream. They travel through the body killing mostly cancer cells. Some healthy cells are killed as well.
The following therapies may be used in conjunction with chemotherapy:
Cancer treatments can cause some side effects like nausea, anemia, pain, or bone loss. Other medications or treatments may be needed to minimize these problems throughout your cancer treatment.
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:
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. It is important to note that mammograms are the most sensitive test currently used to evaluate the breast, but they will miss 10-15% of breast cancers. Mammograms also have a false positive result about 33% of the time. A false positive result occurs when a test suggests an illness that actually does not exist.
There are 2 medications to prevent breast cancer in high-risk, postmenopausal women. These medications increase your chances of having blood clots and stroke. Talk to your doctor about whether medication is right for you.
If you are at very high risk for breast cancer, surgery to remove your breasts before you get cancer (a procedure called prophylactic mastectomy) may be an option.
Canadian Breast Cancer Foundation
Canadian Cancer Society
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Last reviewed December 2015 by EBSCO Medical Review Board Mohei Abouzied, MD, FACP Last Updated: 7/17/2017