"Doctor, is there a magic pill to prevent breast cancer? "
By Ms Lita Chew, Manager,
Oncology Pharmacy, NCC
Chemoprevention refers to the
use of medications to prevent or reduce the risk of cancer.
In 1998 the U.S. Food and Drug Administration (FDA) approved the use
of tamoxifen for the reduction of risk of breast cancer in healthy
high-risk women. One important study was the Breast Cancer Prevention
Trial (BCPT), in which more than 13,000 women were randomly assigned
to receive either tamoxifen or an inactive placebo for five years.
The study showed that tamoxifen reduces the risk of developing invasive
breast cancer by 49% in women who are at increased risk.
Another important prevention trial, the study of Tamoxifen and Raloxifene
(STAR), has begun in 1999. The STAR trial compares these two drugs
to determine which is more effective at reducing invasive breast cancer
and has fewer side effects. This study involves over 22,000 women.
Chemoprevention is not for all women. At this point, it can only benefit
women who are at high risk of developing breast cancer. Potential
side effects of taking tamoxifen include an increased risk of endometrial
cancer, as well as increasing the risk of blood clots and cataracts,
particularly in women over the age of 50. The decision to start chemoprevention
should rest on two major factors: a woman's actual risks and what
those risks mean to her. Women who are considering chemoprevention
need to be aware of all of the potential risks and benefits, and to
weigh these factors carefully before making a final decision.
