Carmine

Various anticancer drugs are used nowadays to treat breast cancer.

Antimetabolites are drugs that act as "dummy" building blocks and are incorporated into the cells' DNA. When cells get ready to divide, a defect occurs in the process and causes them to die. Examples of this class of drugs used for breast cancer treatment are 5 fluorouracfil (5-FU) and methotrexate. 5-FU is a "false" building block for nucleic acids that are part of the genetic structure in the nucleus of the cell. 5-FU is a fluoropyrimidine carbamate class of drug. A new fluoropyrimidine drug has recently been developed known as capecitabine (brand name: Xeloda). This drug can be administered orally and requires an intracellular enzyme to convert it to its active form. Breast cancer cells contain an abundant amount of this enzyme than normal cells, giving capecitabine a selective advantage in destroying cancer cells over normal cells. Capecitabine is presently going through testing process and is not used in the adjuvant setting at present but may be available in the future. The other drug, methotrexate acts by inhibiting an enzyme that is important in providing a building block for DNA. The vitamin folic acid can antagonize this drug action, so this vitamin should while a cancer patient is on methotrexate.

Alkylating agents affect cancer cells in the same manner as radiation. Cyclophosphamide (Cytoxan) is the most commonly used drug of this class. It is usually administered intravenously but can also be given orally on a daily basis. The intravenous form of the drug does not usually cause hair loss (alopecia), but the oral form may. This drug is very effective and is part of most regimens used for cancer adjuvant chemotherapy.

Antineoplastic antibiotics are different from antibiotics used to treat infection in the sense that they are potent inhibitors of DNA replication. The most commonly used drug of this class in breast cancer therapy is doxorubicin (Adriamycin). Adriamycin is extremely active with breast cancer. A related drug, known as metoxantrone (Novantrone) is less frequently. Mitomycin, another drug in this class, is active with breast cancer but is not usually used in adjuvant regimens.

Cisplatin is a heavy metal also used to kill cancer cells. Its efficacy as an anticancer agent was discovered in the late 1970s when scientists were trying to pass electrical currents though Petri dishes of bacterial colonies to determine if the electronic activity inhibited bacterial growth. Interestingly, the bacteria around the platinum electrode died instantly. From this discovery, it was found that platinum leaked into the tissue media and was responsible for killing the bacteria. This observation made way to further investigations that demonstrated that platinum as a potent inhibitor of cell division and an excellent anticancer agent. Most recently, it has been used in ovary and breast cancer treatment with similar results. It has good anticancer activity and can be used in high doses with moderate adverse events.

During cell division, the chromosome line up and migrate to opposite poles on the nucleus of the cell. The apparatus for this process is called the mitotic spindle. Certain drugs block this process in cell division and cause the inability of cells to migrate. Vincistine is an example of this drug, as is a new drug called vinorelbine.

Antimicrotubule agents are unique agents that originated from the Pacific yaw tree. Examples of this class are paclitaxel and docetaxel. They are very potent in killing cancer cells. In a span of a few years, these drugs went from discovery to rapid testing in several cancer types, including breast cancer. Because of their impressive ability to kill cancer cells and a relatively acceptable degree of toxicity to normal cells, they are now part of many regimens for women who have a significant risk of metastatic breast cancer.

Michael Russell Your Independent guide to Breast Cancer