FDA has approved several new drugs and new uses for older drugs in recent years that improve the chances of successfully treating breast cancer. Recent follow-up research shows that Herceptin, in combination with chemotherapy, also may modestly extend the lives of terminal breast cancer patients. Selection of patients who are most likely to benefit from Herceptin is important because of the possible serious risks from the drug, including weakening of the heart muscle that can lead to congestive heart failure. It is not known whether Herceptin has beneficial effects in women with normal levels of the HER2 protein. FDA also approved in September 1998 a test called DAKO HercepTest to measure HER2 protein in tumors.
Doctors know that estrogen promotes the growth of breast cancer cells.
Tamoxifen interferes with the activity of estrogen by slowing or stopping the growth of cancer cells already present in the body. As adjuvant therapy, tamoxifen has been shown to help prevent both the original breast cancer from returning, and also the development of new cancers in the other breast. A National Cancer Institute study showed that the drug reduced the short-term chance of getting breast cancer by 44 percent in women who were judged to be at increased risk for the disease. FDA emphasizes, however, that tamoxifen, manufactured by Zeneca Pharmaceutical Inc., Wilmington, Del., will not eliminate breast cancer risk completely, and should be used only following a medical evaluation of individual risk factors. Xeloda does not kill the cancer cells directly.