Many postmenopausal women take hormonal therapy medicine -- either an aromatase inhibitor or tamoxifen -- after breast cancer surgery and other treatments for hormone-receptor-positive, early-stage breast cancer. Hormonal therapy medicine can reduce the risk of the cancer coming back (recurrence). Hormonal therapy medicine taken after surgery and other treatments is called adjuvant hormonal therapy.
A study found that taking the aromatase inhibitor Femara (chemical name: letrozole) as adjuvant hormonal therapy improved overall survival compared to tamoxifen. These results were presented at the 2008 San Antonio Breast Cancer Symposium.
Other research has shown that aromatase inhibitors are somewhat better than tamoxifen at reducing the risk of breast cancer coming back. (Armidex [chemical name: anastrozole] and Aromasin [chemical name: exemestane] are the other two aromatase inhibitors.) Still, the earlier research didn't show that an aromatase inhibitor improved overall survival compared to tamoxifen. The study reviewed here, called the BIG 1-98 trial, is the first study to show an overall survival benefit for the aromatase inhibitor Femara compared to tamoxifen. Overall survival was 13% better in the women who took Femara compared to the women who took tamoxifen.
The researchers compared the risk of breast cancer coming back in women who started taking tamoxifen and then switched to Femara after several years to the risk of breast cancer coming back in women who took only Femara. All of the women took hormonal therapy medicine for a total of 5 years. The results suggest that taking an aromatase inhibitor for 5 years is somewhat better at reducing the risk of breast cancer coming back compared to starting on tamoxifen and then switching to an aromatase inhibitor. After 5 years, 9.1% of the women who started on tamoxifen and then switched to Femara had the breast cancer come back, compared to 7.3% of the women who took Femara for 5 years.
Research continues to show that an aromatase inhibitor is the best hormonal therapy medicine to start with after initial breast cancer treatment for postmenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer. But tamoxifen is still a good choice, depending on your unique situation. For a number of reasons, including side effects and cost, tamoxifen may be a better choice for some women.
When you're deciding on a treatment plan, keep two things in mind:
- Every woman responds differently to treatment. What works for someone else may not work for you and what works for you may not work for someone else.
- Your treatment plan isn't written in stone. You can always switch medicines if another treatment has greater benefits and fewer side effects.
If you're a postmenopausal woman being treated for hormone-receptor-positive, early-stage breast cancer, talk to your doctor about the differences in benefits and side effects of aromatase inhibitors and tamoxifen. If you're currently taking tamoxifen, discuss whether switching to an aromatase inhibitor makes sense for you. Together, you can decide on a treatment plan that is best for YOU.