Breast cancer, the uncontrolled proliferation of tissues within the ducts, lobules or nipple of the breast, is a life-threatening disease. The cancer begins as a growth of cells within the breast that begin to invade neighboring tissues and eventually circulate to form tumors on tissues throughout the body. Stage four breast cancer is advanced breast cancer that has developed secondary tumors in other tissues, such as the lungs, liver, brain and bone. A number of therapies can be used to treat stage four breast cancer with some success.
Herceptin
A drug called Herceptin can be used to treat metastatic advanced breast cancer. Herceptin is a type of drug called a monoclonal antibody, which works by binding to specific factors on breast cancer cells through the body, and targeting those cells for degradation by the immune system. Herceptin specifically targets types of breast cancer that overproduce a protein called HER2, which is found in high concentrations on the surface of cancer cells. According to Genentech, the drug's manufacturer, Herceptin blocks HER2 function within cancer cells to slow cancer cell growth, and also recruits white blood cells to kill the cancer cells, shrinking the tumor.
Since Herceptin circulates throughout the body, it can attack cancer cells in multiple tissues to treat tumors throughout the entire body. Herceptin is only effective in treating tumors that overproduce the HER2 protein, such as certain tumors that originated in breast tissue.
Avastin
Avastin is a drug that can be used to treat stage four breast cancers. It is approved to treat breast cancer patients with HER2-negative tumors, which do not respond to Herceptin, according to Genentech, Avastin's manufacturer. Avastin works by inhibiting the function of a protein called VEGF, which helps stimulate blood vessel growth. Tumors have the ability to stimulate blood vessel development to provide nourishment and oxygen to their cells, which allows for cancer progression, so Avastin halts cancer growth by preventing blood vessel development.
Like Herceptin, Avastin circulates throughout the body so it is able to target cancer cells in multiple tissues at a time, making it an effective treatment for stage four breast cancer. Since blood vessel development is important in many normal processes, such as wound healing, patients taking Avasin may experience a number of side effects.
Gemzar
Gemzar, also known by its generic name gemcitabine, is a chemotherapy drug used for the treatment of metastatic stage four breast cancer. A study published in "Seminars in Oncology" in 1995 indicates that Gemzar is a pro-drug, which means that it is converted into a cancer-fighting drug within the body. Gemzar works by preventing the cell from replicating its DNA, an essential step in cell proliferation. Without the ability to synthesize DNA, the breast cancer cell can no longer divide and eventually dies, treating the cancer.
Lilly USA, Gemzar's manufacturer, indicates that Gemzar can be used as part of chemotherapy treatment for metastatic stage four breast cancer. Combining Gemzar with another breast cancer drug, paclitaxel, can treat breast cancer more effectively than other paclitaxel alone. Patients taking Gemzar for stage four breast cancer may experience a number of side effects, including low blood cells counts, hair loss and nerve damage, according to Lilly USA.
