Tamoxifen as Prevention Questioned
Popular Breast Cancer Drug May Not Lengthen Life for Most
WebMD News Archive
All in the Numbers continued...
Meanwhile, tamoxifen use is associated with an increased risk for uterine cancer. Tamoxifen is also associated with
increased risk for serious blood clots that can be life-threatening, and for
The researchers concluded it would take a breast cancer risk of greater than
3% to derive a potential mortality benefit from tamoxifen.
The model did show a mortality benefit for tamoxifen users at all levels of
risk if the women had had hysterectomies. The increased risk of uterine cancer
from using tamoxifen does not exist for these women.
"The projected benefits of tamoxifen for women at or near the threshold
risk for breast cancer of 1.67% are very small or nonexistent," Melnikow
and colleagues conclude in the Sept. 1 issue of the American Cancer Society
Melnikow tells WebMD that women with a five-year breast cancer risk of less
than 2.5% or 3% should probably not take tamoxifen, especially if they have not
Tamoxifen vs. Raloxifene
Breast cancer prevention researcher D.
Lawrence Wickerham, MD, of the National Surgical Adjuvant Breast and Bowel
Project (NSABP), tells WebMD that very few women at the low end of the
high-risk scale are taking tamoxifen for prevention.
Wickerham and colleagues recently reported findings from a long-awaited
study comparing tamoxifen to raloxifene for breast cancer prevention in postmenopausal women.
He tells WebMD that the Study of Tamoxifen and Raloxifene (STAR) showed both
drugs worked equally well, reducing breast cancers to about half of what would
have been expected. But raloxifene was found to have a better safety profile,
with a lower risk of causing uterine cancer,
blood clots, and cataracts.
Raloxifene, which is manufactured by Eli Lilly and sold under the brand name
Evista, is widely prescribed for osteoporosis,
but it has not yet been approved for breast cancer prevention.
Fewer Side Effects?
"We viewed raloxifene as the winner, not because it was more effective,
but because it was as effective as tamoxifen with fewer side effects,"
Wickerham says. "Raloxifene may prove to be the drug that makes prevention
treatment both practical and effective."