Breast cancer chemotherapy

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Assistant Editor(s)-In-Chief: Jack Khouri

Overview

Breast cancer chemotherapy refers to the use of cytotoxic drugs (chemotherapy) in the treatment of breast cancer.

Types

Chemotherapy can be given both before and after surgery. Neoadjuvant chemotherapy is used to shrink the size of a tumor prior to surgery. Adjuvant chemotherapy is given after surgery to reduce the risk of recurrence. Palliative chemotherapy is used to control (but not cure) the cancer in settings in which the cancer has spread beyond the breast and localized lymph nodes.

Regimens

Several different chemotherapy regimens may be used. Determining the appropriate regimen depends on many factors, including the character of the tumor, lymph node status, and the age and health of the patient. In general, chemotherapy has increasing side effects as the patient's age passes 65. The following is a list of commonly used adjuvant chemotherapy for breast cancer:

• CMF: cyclophosphamide, methotrexate, and 5-fluorouracil given 4-weekly for 6 cycles
• FAC (or CAF): 5-fluorouracil, doxorubicin, cyclophosphamide given 3-weekly for 6 cycles
• AC (or CA): Adriamycin (doxorubicin) and cyclophosphamide given 3-weekly for 4 cycles
• AC-Taxol: AC given 3-weekly for 4 cycles followed by paclitaxel given either 3-weekly for 4 cycles or weekly (at a smaller dose) for 12 weeks
• TAC: Taxotere (docetaxel), Adriamycin (doxorubicin), and cyclophosphamide given 3-weekly for 6 cycles
• FEC: 5-fluorouracil, epirubicin and cyclophosphamide given 3-weekly for 6 cycles
• FECD: FEC given 3-weekly for 3 cycles followed by docetaxel given 3-weekly for 3 cycles
• TC: Taxotere (docetaxel) and cyclophosphamide given 3-weekly for 4 cycles
• Dose dense regimen: Some of the regimens above (e.g. AC followed by paclitaxel) may be given in a shorter period (i.e. every 2 weeks instead of every 3 weeks).
• In addition to chemotherapy, trastuzumab may also be added to the regimen depending on the tumor characteristics (i.e. HER2/neu status) and risk of relapse. It is usually given either 3 weekly or weekly for a total duration of 1 year.

Since chemotherapy affects the production of white blood cells, granulocyte colony-stimulating factor (G-CSF) is sometimes administered along with chemotherapy. This has been shown to reduce, though not completely prevent, the rate of infection and low white cell count. Most adjuvant breast cancer chemotherapy regimens do not routinely require growth factor support except for those associated with a high incidence of bone marrow suppression and infection. These may include chemotherapy given in the dose dense fashion i.e. 2-weekly instead of 3-weekly or TAC chemotherapy (see above).