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, called the BIG 1-98 trial, found that taking the aromatase inhibitor Femara (chemical name: letrozole) for 5 years as the first adjuvant hormonal therapy medicine improved overall survival by 13% compared to taking tamoxifen for 5 years.
These results are similar to earlier results from the same study presented at the 2008 San Antonio Breast Cancer Symposium. The BIG 1-98 trial is the first study to show an overall survival benefit for Femara compared to tamoxifen.
The researchers divided the more than 8,000 postmenopausal women diagnosed with hormone-receptor-positive breast cancer in the study into four groups:
- group one got 5 years of Femara
- group two got 5 years of tamoxifen
- group three got 2 years of tamoxifen then 3 years of Femara
- group four got 2 years of Femara then 3 years of tamoxifen
While Femara alone for 5 years was better than tamoxifen alone for 5 years, there was little difference in the risk of the cancer coming back between the women who got Femara alone or Femara and then tamoxifen. The women who took tamoxifen first and then switched to Femara were more likely to have the cancer come back someplace else in the body compared to women who took Femara first and then switched to tamoxifen.
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.