Researchers discovered that certain breast cancer tumors are either estrogen positive or negative. This simply means that some tumors respond to estrogen and others do not. Tamoxifen is a SERM. This term means Selective Estrogen Receptor Modulator. Tamoxifen blocks estrogen to some organs and yet it allows estrogen to work on other organs. Tamoxifen is the hormonal therapy that has been studied the most to date. In estrogen positive women, it blocks estrogen from going to the breast. Somehow it lets estrogen still work in the liver (reducing high cholesterol) and increasing the chance of endometrial cancer. Most women will receive a benefit from tamoxifen - it dramatically reduces your chances of incurring an invasive breast cancer. The current theory has most breast cancer patients on tamoxifen for 5 years post all other treatments. Many high risk women are given the choice to take tamoxifen before they ever develop breast cancer. As with any medical treatment, it is up to you, the patient, to weigh the odds and make an informed decision. Many pre-menopausal women will experience menopausal side effects with tamoxifen. Some of the side effects of tamoxifen mimic natural menopause - hot flashes, weight gain, irritability. Not all women experience all of these side effects and many of them can be controlled through diet and/or medication. Some of the risks of tamoxifen include the incidence of pulmonary emobli and phlebitis. A benefit is an increase in bone density. Most women tolerate tamoxifen fairly well. There are, however, some women who can not go through five years on tamoxifen.
Although Tamoxifen is the most prescribed hormonal therapy for breast cancer, there are others on the market. Many are in research studies or clinical trials. Some therapies are offered currently for metastatic disease and have not yet been FDA approved for post-breast cancer. Raloxifene is a drug originally designed for osteoporosis, which has been compared to tamoxifen in the STAR trial. Other hormones used in metastatic disease include Fareston and Femara. Some oncologists switch their patients to these if they are unable to tolerate Tamoxifen. Studies are also underway which suggest that after a period of time, women become resistent to tamoxifen. Women who are estrogen negative receive little or no benefit from tamoxifen.
A newer type of hormonal therapies are called aromatase inhibitors. Aromatase is a enzyme found in the body which converts testosterone and androstenedione to estrogen. Arimidex is an example of an aromatase inhibtor. In studies, it has proven to be as effective as tamoxifen in metastatic disease. Studies are ongoing in the use of armoatase inhibitors as adjuvant therapy.
The copyright of the article Hormonal Therapy in Breast Cancer Research is owned by Linda Bily. Permission to republish Hormonal Therapy in print or online must be granted by the author in writing.
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