Breast cancer refers to a number of cancers that develop from the various cell types of the breast. According to the National Cancer Institute, there were 194,280 cases of breast cancer diagnosed in the United States in 2009, with 192,370 of those affected being female. There are a number of effective medication treatment options for breast cancer, which can be used alone or in combination with other therapies to treat breast cancer.
Hormone Therapies
Breasts are hormonally regulated tissues, which respond to levels of several hormones that control breast cell behavior throughout life. Some forms of breast cancer remain sensitive to hormones such as estrogen, which promotes proliferation of breast cancer cells and growth of the tumor.
A number of medications are targeted at cancers made up of cancer cells containing estrogen receptors, the protein found within the cells that makes them sensitive to estrogen. These are known as ER+ cancers. Tamoxifen is an effective drug to fight ER+ cancers, since the drug interacts with the estrogen receptor and blocks estrogen signaling, slowing the growth of the tumor. A class of drugs called aromatase inhibitors can also be used to treat ER+ breast cancer, since they inhibit the formation of estrogen, cutting off the supply of estrogen to the tumor. There are several aromatase inhibitors on the market, all of which are effective in treating some forms of breast cancer.
Chemotherapy
Breast cancer can be treated with chemotherapy, which is delivery of toxic drugs to the cancer cells to cause remission of the tumor. Two commonly used chemotherapy agents used to treat breast cancer are doxorubicin and cyclophosphamide. Doxorubicin is used to interfere with replication of genetic material within cancer cells, ultimately preventing the cell from making the proteins it needs to survive, and eventually killing the cell. Cyclophosphamide is a type of chemical called an alkylating agent, which interferes with the normal function of DNA and eventually leads to cell death.
These drugs may be used in combination with other chemotherapy agents. In general, chemotherapy drugs are also toxic to normal cells, so care must be taken to selective target tumor cells when possible. Chemotherapy drugs can have a wide range of side effects, depending of the combination of drugs used, and the dose level and duration of treatment.
Targeted Therapies
Some types of breast cancer have characteristic genetic mutations that lead to development of the tumor. One such mutation is found in HER2, a protein found on the surface of the cell which regulates when the cell divides. In many cases of breast cancer, too much HER2 protein is created, so it is always telling the cell to divide, leading to formation of a tumor. A drug called Herceptin has been developed to target HER2-overproducing forms of cancer.
Herceptin works by binding to the HER2 protein on the cancer cell, and triggers your immune system to kill the cell. It may also block the activity of HER2 on the cancer cell to stop the signal telling the cancer cell to divide. Herceptin has been shown to be effective in treating metastatic breast cancers expressing the mutant HER2 receptor. Some common side effects of taking Herceptin are chills, fever, nausea and an increased risk of heart problems.
