Dr. Kathy Albain, a breast cancer specialist at Loyola University Medical Center near Chicago, and colleagues found women who initially took the drugs anastrozole and fulvestrant together at the same time lived more than six months longer than women who took anastrozole alone, with fulvestrant given later when the disease progressed.
"This study is the first to show that combination hormonal therapy alone without chemotherapy improves survival in advanced breast cancer," Albain said in a statement. "This most likely will change the standard of care for how we treat these patients."
First author Dr. Rita Mehta of the University of California at Irvine, said anastrozole, or Arimidex, is a pill that is taken daily -- a class of medications called aromatase inhibitors. It works by decreasing the amount of estrogen the body makes -- estrogen fuels breast cancer.
Fulvestrant, or Faslodex, is given by injection and binds to estrogen receptors, blocking the effect estrogen has on cancer cells, Mehta said.
The study involved 707 post-menopausal women who had metastatic breast cancer that was hormone-receptor-positive. Women who received the standard regimen survived a median of 41.3 months. Women who received the two drugs in combination survived a median of 47.7 months.
The findings were published in the New England Journal of Medicine.