Aromatase inhibitors, a type of hormone therapy used to treat advanced breast cancer in postmenopausal women, result in a small but significant increase in overall survival when compared to other hormone treatments, according to a new systematic review of studies.
In addition, aromatase inhibitors -- drugs known as Arimidex, Aromasin and Femara -- are less likely to cause blood clots and vaginal bleeding than other hormone treatments, said review co-author Judith Bliss of the Institute of Cancer Research in London.
The review analyzed 30 studies involving the treatment of advanced breast cancer, encompassing more than 10,000 postmenopausal women.
Bliss and colleagues were surprised at how few of the reviewed studies presented data on overall survival for women taking aromatase inhibitors. "Survival data was only available for about half of the women," Bliss said.
The available data showed an 11 percent reduction in the risk of death compared to women not receiving aromatase inhibitors.
The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The treatment of advanced breast cancer in women who have gone through menopause usually involves a combination of surgery, radiation, chemotherapy, hormonal and biological therapies. In many breast cancers, estrogen stimulates tumor growth. Aromatase inhibitors work by limiting a woman's production of estrogen.
Several aromatase inhibitors, including anastrozole (Arimidex), exemestane (Aromasin) and letrozole (Femara) have been available for clinical use for the past decade or so.