Q: What is tamoxifen?
Dr. Donnica: Tamoxifen citrate (name brand
"Nolvadex"; Zeneca Pharmaceuticals) is a medicine in the selective
estrogen receptor modulator (SERM) class. Its primary action in the breast
is as an "anti-estrogen". In other parts of the body, however, its
actions mimic those of estrogen (e.g. lowering LDL cholesterol and slowing bone
loss). Used to treat breast cancer, it was approved by the FDA in 10/98 to
prevent breast cancer in women at high risk.
The FDA approval was based largely upon the results of the Breast Cancer Prevention
Trial (BCPT) conducted by the National Cancer Institute (NCI) from 1992-1997.
This double blind placebo-controlled study of 13,000 healthy women at high risk
for breast cancer, showed that tamoxifen reduced breast cancer risk by 44%.
In fact, the data were so impressive, that the trial was actually stopped 14
months early so that the women on placebo could be offered the opportunity to
benefit from tamoxifen treatment as well.
Tamoxifen is also used to treat melanoma and ovarian
cancer. For prevention of breast cancer, it is usually given twice daily and
may cost approximately $100 a month.
As with all medications, tamoxifen's benefits do not
come without risks. Like estrogen, tamoxifen increases the risk of endometrial
cancer and blood clots. Unlike estrogen, tamoxifen may increase menopausal
symptoms such as hot flashes. Because of the associated risks, the FDA recommends
that tamoxifen should only be prescribed for women at high risk for breast cancer.
Created: 11/16/2000  - Donnica Moore, M.D.