Study Finds Arimidex Better Than Tamoxifen in Barring Tumors in Healthy Breast
March 2002: Recent research indicates that Arimidex, a new hormone-blocking drug works better than
tamoxifen in preventing early-stage breast cancer from developing into tumors in the healthy breast.
In a large breast-cancer treatment study, women taking Arimidex were
found to be less than half as likely as those taking tamoxifen to develop a new cancer in the other breast. The study was paid for by Arimidex's maker,
The study involved 9,366 post- menopausal women with early- stage breast cancer.
One-third of them were given tamoxifen after their tumors were removed, another third got Arimidex and the rest got both the drugs.
So far, 14 women, or 0.4 percent, in the Arimidex group have developed a new tumor in their other breast, compared with 33 women, or 1.1 percent, in the tamoxifen group.
When the scientists restricted their calculations to the women whose cancers they knew were driven by estrogen, the risk of new cancers in the opposite breast with Arimidex was 64 percent lower than with
About 700,000 new cases of breast cancer are diagnosed every year worldwide. Estrogen fuels the growth of more than half of all breast cancers, especially those in older women.
Currently, tamoxifen is the treatment of
choice for this condition. It is believed to work by preventing estrogen from linking up to a receptor on cancer cells.
Arimidex is among a new class of cancer drugs called aromatase inhibitors, which work differently, by blocking production of estrogen. Arimidex is not effective on cancers that are not driven by estrogen or on pre-menopausal women.