Chemotherapy is the term used to describe the use of chemicals, or 'chemotherapeutic agents', to kill cancerous cells in the body. Chemotherapy drugs target living cells in the body that are dividing rapidly (which is what a cancer cell does), and this is why other cells in the body that reproduce rapidly normally are also affected, leading to hair loss, decreased production of blood cells and inflammation of the cells lining the digestive tract.
Typically, a course of chemotherapy will include one or more drug types, which can be delivered orally or directly into the bloodstream (intravenous chemotherapy), and on occasion directly to the organ or tissue affected. In some cases more permanent devices can be set up, often called 'long term access devices' which remove the need for a needle every time treatment is required.
With breast cancer, chemotherapy is generally used after surgery to remove any tumour/s and/or to remove of lymph nodes, with the aim of killing any cancer cells that may have been left behind and so to minimise any risk of the cancer returning or spreading to other parts of the body (metastasis). In some instances chemotherapy can also used to shrink a tumour before surgery takes place.
Where breast cancer has reached an advanced stage, chemotherapy is used as an ongoing treatment to attack and remove any cancer cells that remain in the body.
Visit the Cancer Australia website for more information on chemotherapy as a treatment for breast cancer.