Adjuvant Breast Cancer

Colorful pills.

Adjuvant breast cancer therapy refers to any additional breast cancer treatment a woman receives following the primary treatment for the breast cancer -- which typically is surgery (either a lumpectomy, partial mastectomy or mastectomy) to remove the tumor. Following the breast surgery, adjuvant therapy such as radiation therapy, hormone therapy, chemotherapy or targeted therapy is then given to help reduce the risk that the cancer will come back.

While specialized tests following surgery may show that the breast cancer has not spread to the lymph nodes, it can be too early to detect whether or not a few cancer cells have broken away and have spread to other parts of the body. For this reason oncologists give adjuvant therapy to help kill any remaining cancer cells left behind following surgery. Breast cancer adjuvant therapy may include one or more of the following treatments:

Radiation Therapy

The use of high-energy rays to kill the breast cancer cells, radiation therapy can be given internally, where the radiation is placed in a small tube and inserted into the breast through a tiny incision, or externally, meaning the radiation stems from a large machine.

Hormone Therapy

Prior to diagnosis, a biopsy is usually performed to confirm the presence of cancer cells in the breast. Other tests are then performed on this tissue to determine whether the tumor is hormone receptor positive or negative. If it is hormone receptor positive, it means the cancer relies on the hormones estrogen and progesterone to grow. Hormone therapies such as tamoxifen, LH-RH agonists or aromatase inhibitors are then used to block the cancer cells from using these hormones.


Chemotherapy works to kill the rapidly dividing cancer cells. Studies have shown that the use of adjuvant chemotherapy helps to prevent early-stage breast cancer from recurring. Typically, combinations of two or more chemotherapy agents are given intravenously or by a pill following surgery.

Targeted Therapy

Approximately 20 to 25 percent of breast cancers are HER2-positive, which means they overexpress a gene that stimulated the growth of breast cancer. In women with HER2-positive breast cancer, a targeted therapy can be given that works only in this specific type of breast cancer.


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