What is breast cancer?

Breast cancer is a condition in which breast cells grow abnormally and divide without control or order. Most breast cancers start in the lining of the milk ducts; these are called ductal cancers. Less commonly, breast cancers start in the milk lobules; these are called lobular cancers.

Cancer cells often begin “in situ,” or confined to the milk ducts or lobules. Sometimes, they then grow outside of the milk ducts, a process called invasion or infiltration. Once the cells become invasive, they might spread beyond the breast to lymph nodes and other organs through the bloodstream, a process referred to as metastasis.

How is breast cancer treated?

There are two types of treatment for breast cancer. The first type is referred to as local therapy. Local therapy involves treating the breast tissue itself to lessen the chance of local recurrence (return of the cancer). This treatment can be accomplished by either breast conservation (lumpectomy with whole breast irradiation therapy) or mastectomy (with or without chest wall irradiation).

The second type of treatment is called systemic therapy. Systemic therapy is meant to treat the body and uses medications to target and destroy cancer cells that have spread beyond the breast. Chemotherapy and hormonal therapy (estrogen-blocking medications) are examples of systemic treatments. Most people with breast cancer benefit from both local and systemic treatment.

What is breast conservation treatment?

Breast conservation treatment preserves (saves) normal breast tissue while removing the cancer. A “lumpectomy” is performed, and then the remaining breast tissue is treated for 4-5 weeks with radiation therapy. In some patients, options such as a shorter radiation course or even a one-time dose of intra-operative radiation are possible.

Why are lymph nodes removed?

Lymph nodes under the arm can be the first site where breast cancer spreads. The only way to determine whether breast cancer has spread to the lymph nodes is to remove and analyze them. Lymph node removal is reserved for individuals who have invasive breast cancer, whether they have a lumpectomy or a mastectomy. Information from lymph node analysis is used to decide whether the patient should have systemic therapy after the local treatment. Sentinel lymph node biopsy can usually be performed in an effort to remove fewer lymph nodes.

What is breast reconstruction?

Many people who have a mastectomy choose breast reconstruction. Breast reconstruction is done by using either an implant (silicone or saline) or one's own tissue, which is usually transferred from the lower abdomen. The most common tissue flap reconstruction is called the DIEP (deep inferior epigastric perforator) flap procedure and does not involve muscles from the abdominal wall. Reconstruction can be done at the time the mastectomy is done, or later. However, reconstruction after radiation therapy can be more challenging.


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 10/29/2015...#5563