New Early Breast Cancer Treatment

Medical researchers say a new breast cancer drug is better than the "gold standard" - that is, the best treatment now available - in preventing some women in the early stages of the disease from developing a new tumor in the other breast.

The drug, called anastrozole, is produced by AstraZeneca PLC under the brand name Arimidex.

In research presented at the 3rd European Breast Cancer Conference, scientists said the drug outperformed tamoxifen - currently the best available treatment, also made by Astrazeneca - in a trial of women with early breast cancer.

Women who were given anastrozole for two and a half years had a 58 percent lower risk of developing a new tumor in the other breast than those taking tamoxifen.

"It is an important finding. The reduction in the development of contralateral (other) breast cancer was very much greater than we had anticipated," Dr. Jeffrey Tobias of University College Hospital London, an architect of the study, told Reuters.

Tamoxifen cuts the risk of a new cancer in the other breast by 50 percent and anastrozole slashes it in half again.

The study, one of the largest breast cancer trials ever conducted, involved more than 9,000 women who were given either anastrozole, tamoxifen or a combination of both. The combination therapy was no better than tamoxifen alone.

Anastrozole works by inhibiting production of the female hormone oestrogen in women who have passed the menopause. Oestrogen is linked to the development of cancer. Most cases of breast cancer are in post-menopausal women.

But the drug does not work in younger women and it may increase the risk of fractures or brittle-bone disease.

Tobias said women given anastrozole had fewer side effects such as blood clots, hot flushes and cancer of the uterus than the tamoxifen group.