New Drug Promising for Advanced Breast Cancer

A drug called exemestane may be a more effective first-line agent than tamoxifen for postmenopausal women with advanced breast cancer, European researchers report. Tamoxifen works by blocking the effects of estrogen on tumor cells and is the most widely prescribed drug for breast cancer treatment. Exemestane -- which is a member of a newer class of drugs called aromatase inhibitors -- decreases the overall amount of estrogen in the body. Both tamoxifen and aromatase inhibitors only work in patients who have breast tumors that carry hormone receptors, meaning that estrogen fuels the cancer growth. Exemestane is currently approved for the treatment of advanced breast cancer in postmenopausal women whose tumors no longer respond to tamoxifen. To see if exemestane would be an effective first-line agent, Dr. Robert Paridaens of the Universitair Ziekenhuis in Leuven, Belgium, and others randomly assigned 120 postmenopausal women with breast cancer that had spread to other areas of the body to daily treatment with exemestane 25 mg or tamoxifen 20 mg. Independent reviewers, who didn't know which woman had been given what treatment, saw improvement in 41 percent of women treated with exemestane compared to just 17 percent of women treated with tamoxifen.