Post-menopausal women with a certain type of metastatic breast cancer may have a new treatment option that could lengthen their lives, according a study led by UC Irvine oncologist Rita Mehta, MD. The findings were presented today at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium.
The combination of the two anti-estrogen drugs anastrozole and fulvestrant extended the median survival time of women with hormone receptor-positive metastatic breast cancer by more than six months compared to those who underwent standard treatment with anastrozole alone.
Mehta says the results of the phase III trial are particularly exciting because “these patients have not had a new treatment that gave them an overall survival benefit in more than a decade.”
Both drugs are currently used in treating breast cancer, though not in combination. Anastrozole (also known as Arimidex) reduces the production of tumor-promoting estrogen, while fulvestrant (Faslodex®) interferes with the receptors that allow estrogen to signal cells to grow and reproduce.
Researchers think it’s these two different modes of action together that make the combination so effective against hormone receptor-positive breast cancer, the subtype that accounts for more than half of all breast cancers.
“The next step for researchers,” she says, “would be to try the combination in even earlier stages of breast cancer to test whether long-term cures could be increased at those stages.”
The SWOG S0226 trial study was conducted by the SWOG clinical trials network, previously known as the Southwest Oncology Group.