Breast Cancer

The breast is made up of lobes and ducts. Each breast has 15 to 20 sections called lobes. Each lobe has many smaller sections called lobules. Lobules end in dozens of tiny bulbs that can make milk. The lobes, lobules, and bulbs are linked by thin tubes called ducts.

Each breast also has blood vessels and lymph vessels. The lymph vessels carry an almost colorless, watery fluid called lymph. Lymph vessels carry lymph between lymph nodes. Lymph nodes are small, bean-shaped structures found throughout the body. They filter lymph and store white blood cells that help fight infection and disease. Groups of lymph nodes are found near the breast in the axilla (under the arm), above the collarbone, and in the chest.

The most common type of breast cancer is ductal carcinoma, which begins in the cells of the ducts. Cancer that begins in the lobes or lobules is called lobular carcinoma and is more often found in both breasts than are other types of breast cancer. Inflammatory breast cancer is an uncommon type of breast cancer in which the breast is warm, red, and swollen.

A family history of breast cancer and other factors increase the risk of breast cancer.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk for breast cancer.

Risk factors for breast cancer include the following:

• A personal history of invasive breast cancer, ductal carcinoma in situ (DCIS), or lobular carcinoma in situ (LCIS).
• A personal history of benign (noncancer) breast disease.
• A family history of breast cancer in a first-degree relative (mother, daughter, or sister).
• Inherited changes in the BRCA1 or BRCA2 genes or in other genes that increase the risk of breast cancer.
• Breast tissue that is dense on a mammogram.
• Exposure of breast tissue to estrogen made by the body. This may be caused by:
  • Menstruating at an early age.
  • Older age at first birth or never having given birth.
  • Starting menopause at a later age.
• Taking hormones such as estrogen combined with progestin for symptoms of menopause.
• Treatment with radiation therapy to the breast/chest.
• Drinking alcohol.
• Obesity.

Older age is the main risk factor for most cancers. The chance of getting cancer increases as you get older.

Breast cancer is sometimes caused by inherited gene mutations (changes).

The genes in cells carry the hereditary information that is received from a person’s parents. Hereditary breast cancer makes up about 5% to 10% of all breast cancer. Some mutated genes related to breast cancer are more common in certain ethnic groups.

Women who have certain gene mutations, such as a BRCA1 or BRCA2 mutation, have an increased risk of breast cancer. These women also have an increased risk of ovarian cancer, and may have an increased risk of other cancers. Men who have a mutated gene related to breast cancer also have an increased risk of breast cancer.

Signs of breast cancer

These and other signs may be caused by breast cancer or by other conditions. Check with your doctor if you have any of the following:

• A lump or thickening in or near the breast or in the underarm area.
• A change in the size or shape of the breast.
• A dimple or puckering in the skin of the breast.
• A nipple turned inward into the breast.
• Fluid, other than breast milk, from the nipple, especially if it's bloody.
• Scaly, red, or swollen skin on the breast, nipple, or areola (the dark area of skin around the nipple).
• Dimples in the breast that look like the skin of an orange, called peau d’orange.

If cancer is found, tests are done to study the cancer cells to determine the best treatment path.

Radiation therapy

Radiation therapy is uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy:

• External radiation therapy uses a machine outside the body to send radiation toward the area of the body with cancer.
• Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.

The way the radiation therapy is given depends on the type and stage of the cancer being treated. External radiation therapy is used to treat breast cancer. Internal radiation therapy with strontium-89 (a radionuclide) is used to relieve bone pain caused by breast cancer that has spread to the bones. Strontium-89 is injected into a vein and travels to the surface of the bones. Radiation is released and kills cancer cells in the bones.

Chemotherapy

Chemotherapy (also called chemo) uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Chemotherapy for breast cancer is usually systemic, meaning it is injected into a vein or given by mouth. When given this way, the drugs enter the bloodstream to reach cancer cells throughout the body.

Immunotherapy

Immunotherapy helps a person's immune system fight cancer. Your doctor may suggest biomarker tests to help predict your response to certain immunotherapy drugs. 

For more information, visit Cancer.gov 

Source: PDQ® Adult Treatment Editorial Board. PDQ Breast Cancer Treatment. Bethesda, MD: National Cancer Institute. This information should not be used to make decisions about insurance reimbursement.