Breast cancer is one of the most common cancers in the United States, accounting for more than 190,000 new diagnoses and more 40,000 deaths in 2009, according to the National Institute of Cancer. Breast cancer occurs when cells in the breast develop genetic mutations that alter the cells' behavior, leading to uncontrolled cell proliferation and the formation of a tumor. As the cancer progresses, the cancer cells migrate throughout the body to develop secondary tumors in vital organs such as the brain, lung and the bones, which can ultimately lead to death. Breast cancer can be treated with radiation, but this form of therapy increases the risk of developing other forms of cancer in the future. A number of treatment options, other than radiation therapy, are designed to kill cancer cells and shrink breast tumors.
Breast Cancer Surgeries
Most breast cancer cases require surgical therapy, in which the cancer cells are removed from the body. Breast cancer surgeries fall into two general categories: breast-conserving surgeries, also called lumpectomies, or breast-removing surgeries, also called mastectomies. If breast cancer is detected early, before the tumor cells have had a chance to invade neighboring tissue, a lumpectomy is often performed. A lumpectomy involves removing the tumor but leaving the remaining breast tissue, as well as the overlying skin intact. A lumpectomy may be followed with other forms of treatment to prevent cancer recurrence.
If the tumor is more advanced, a mastectomy may be required to ensure removal of all the cancerous tissue. Some forms of mastectomy leave the overlying skin, areola and part of the nipple intact to allow for breast reconstruction surgery. Very advanced forms of cancer may require a radical mastectomy, in which the entire breast, overlying skin, nipple and underlying chest muscles are removed to prevent cancer recurrence.
Herceptin
Herceptin is a therapeutic that falls under a class of therapies called immunotherapy. Herceptin is an antibody, which is designed to bind to a mutated protein found on the surface of the cells in some forms of breast cancer. Herceptin binds the protein HER-2/neu, which is a mutated protein that promotes cancer cell growth. It is found in high amounts on the surface of cancer cells, but not on normal cells. Herceptin works by binding to this protein and stimulating the immune system, causing it to attack the cancer cell to kill the cell. Herceptin may also prevent HER-2/neu signaling to the cell, preventing the transmission of proliferative signals and slowing the growth of the tumor cells, according to Genentech, the drug's manufacturer.
Tamoxifen
Tamoxifen is a form of hormone therapy used to treat breast cancer. Normal breast cells are able to detect circulating estrogen levels using a protein called the estrogen receptor, or ER. Activation of the ER leads to breast cell proliferation, which occurs naturally during the menstrual cycle and pregnancy. Many forms of cancer also express ER, and these cancer cells respond to circulating estrogen and proliferate, so estrogen actually promotes cancer growth. Tamoxifen works by blocking the activation of ER, so the cancer cells no longer receive proliferative signals from estrogen, according to the National Cancer Institute. Tamoxifen therapy is a good alternative to radiation therapy for the treatment of breast cancers that are responsive to estrogen.
