Tamoxifen, as described by the National Cancer Institute, is a drug that "interferes with the activity of estrogen, a female hormone." The U.S. Food and Drug Administration-approved drug is currently marketed under the manufacturer's trademark Nolvadex. Doctors prescribe the drug to treat women and men diagnosed with breast cancer. It is also prescribed by some doctors as a preventative for individuals at high risk for breast cancer.
Pioneer Research
Research done by ICI Pharmaceuticals (now known as Zeneca) in the 1950s laid the groundwork for the development of Tamoxifen. Researchers discovered that oral contraceptives inhibited the amount of estrogen produced by the body. This created the foundation for the manufacture of a group of drugs known as triphenylethylenes.
The 1970s
The early research into triphenylethylenes focused on birth control, but groups of cancer researchers quickly realized that these drugs might also be useful as estrogen antagonists to inhibit the growth of cancer cells, specifically breast cancer cells. During laboratory testing at ICI Pharmaceuticals in the 1970s, the estrogen receptor alpha ligant (a protein) was found to bond to estrogen and estrogendiol to create new cells. Tamoxifen inhibited this bonding process and slowed the creation of cancer cells.
Clinical Testing
The Breast Cancer Prevention Trial, conducted by Dr. D. Lawrence Wickerham who directed the National Adjuvant Surgical Breast and Bowel Project, announced the findings of a five-year, 13,000 personal clinical test in 1999. The clinicians reported that "invasive breast cancer" was reduced by 66 percent in women using Nolvadex (Tamoxifen's marketed name) over the course of the five-year study. Cases of atypical hyperplasia and lobular carcinoma in situ (breast cancer located in the milk-producing cells) in the 826 study volunteers with a prior history of this type of cancer were reduced nearly 86 percent. Wickerham suggested that the results were an indication that doctors should "consider prophylactic treatment with Tamoxifen" for women with both types of breast cancers.
Current Use
Tamoxifen is currently prescribed to women older than 35 who are high risk candidates as defined by the perimeters of the Gail Model Risk Assessment. V.C. Jordan, of the Robert H. Lurie Cancer Center in Chicago, reports that "Taxoxifen is currently the endocrine treatment of choice for all stages of breast cancer and is the gold standard for antiestrogen treatment."
Challenges
Opponents of Tamoxifen use point out that the clinical volunteers in the Breast Cancer Prevention Trial did not have an increased survival rate, and that the drug merely prolonged life. The side effects of the drug are frequently cited as a balance to any advantages. These include increased incidence of lung blood clots, endometrial cancer and cataracts. Higher incidents of strokes were also recorded among study participants.
Tags: breast cancer, cancer cells, breast cancer, Breast Cancer Prevention, Cancer Prevention, Cancer Prevention Trial, high risk
