Aromasin Approved for Women with Early-Stage Disease
Reviewed article: "Aromasin Approved for Women with Early-Stage Disease"
The U.S. Food and Drug Administration (FDA) has approved Aromasin (chemical name: exemestane) to treat post-menopausal women with hormone-receptor-positive, early-stage breast cancer after two to three years of tamoxifen (for a total of five years of hormonal therapy). Pfizer Inc, which makes Aromasin, announced the FDA approval on October 5, 2005.
Background: Aromasin, an aromatase inhibitor, was originally approved as a second-line hormonal therapy for post-menopausal women with hormone-receptor-positive metastatic breast cancer (cancer that has spread beyond the breast and area lymph nodes). "Second-line" means Aromasin was used when the cancer stopped responding to tamoxifen or to another hormonal therapy.
In January 2005, the American Society for Clinical Oncology updated its guidelines for hormonal therapy. These guidelines now state that treatment after surgery for post-menopausal women with early-stage, hormone-receptor-positive breast cancer should include an aromatase inhibitor.
Aromatase inhibitors reduce the amount of estrogen available to stimulate the growth of hormone-receptor-positive breast cancer. After menopause, most of the body's estrogen is made from another hormone, androgen. Aromatase inhibitors stop the enzyme called aromatase from turning androgen into estrogen. That means less estrogen in the bloodstream, less estrogen reaching estrogen receptors, and less cancer cell growth. Other types of anti-estrogen therapies work differently from aromatase inhibitors. SERMs (selective estrogen receptor modulators such as tamoxifen) and ERDs (estrogen receptor downregulators) block estrogen's ability to lock onto cancer cells and "turn on" their growth.
The research behind the approval: The FDA's approval of Aromasin to treat early-stage, hormone-receptor-positive breast cancer in post-menopausal women after they've taken tamoxifen for two to three years is based on a 2004 research study of 4,742 women. The study compared two groups:
- women who started with tamoxifen for two to three years, then switched to Aromasin for another two to three years (for a total of five years of hormonal therapy), and
- women who stayed on tamoxifen for the full five years.
The women who switched to Aromasin were about a third less likely to have the cancer come back or to develop a new cancer in the other breast. (The relative risk reduction was 32%. The absolute risk reduction was 3-4%. Visit our page on Understanding Breast Cancer Risk for more information on relative and absolute risk.)
What breastcancer.org says about this article…
Aromasin Approved for Women with Early-Stage Disease
If you're a post-menopausal woman with early-stage, hormone-receptor-positive disease, and you're taking tamoxifen, now you have another treatment option to consider. After two to three years of tamoxifen, you may be able to get greater benefit from switching to an aromatase inhibitor for the remaining two or three years (rather than staying on tamoxifen for the full five years). Two aromatase inhibitors have been tested after two to three years of tamoxifen: Aromasin and, in past studies, Arimidex (chemical name: anastrozole).Also, if you're on tamoxifen for less than two years and have difficulty with side effects, your doctor might suggest switching to an aromatase inhibitor sooner.
Choose the best treatment for YOU: See your doctors regularly for follow-up after treatment. This is the best time to discuss your current treatment plan as well as new options that might benefit you. As new advances are made, you'll want to be sure you consider them.
It's important to remember that every woman responds to treatment differently. Changing your treatment plan can make you anxious—particularly if everything is going pretty well and you've gotten used to your current plan. Talk to your doctor about the best options for YOU. Together, you can develop a treatment plan that best suits you and your style of making decisions.
And stay tuned to Breastcancer.org for updates on all the new research on hormonal therapies.