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). Treatments given after surgery are called "adjuvant" -- in this case adjuvant hormonal therapy.
The latest results from the BIG 1-98 trial found that the aromatase inhibitor Femara (chemical name: letrozole) was better at reducing the risk of recurrence and improving survival compared to tamoxifen when taken for 5 years as the first hormonal therapy after surgery.
The results were published early online on Oct. 21, 2011 in The Lancet Oncology.
In the BIG 1-98 trial, more than 8,000 postmenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer were randomly assigned one of four treatments after surgery:
- 5 years of Femara
- 5 years of tamoxifen
- 2 years of tamoxifen then 3 years of Femara (sequential therapy)
- 2 years of Femara then 3 years of tamoxifen (sequential therapy)
Half the women were followed for more than 8 years; the others for shorter times. The researchers then compared the outcomes of the different treatments.
Using two types of statistical analysis, the researchers found that women who got 5 years of Femara had:
- better disease-free survival (living without the cancer coming back)
- better overall survival (living whether or not the cancer came back)
compared to women who got 5 years of tamoxifen.
Women who got either of the sequential therapies (Femara for 2 years, then tamoxifen for 3, or tamoxifen for 2 years, then Femara for 3) had about the same recurrence risk, and the same overall survival, as women who got only Femara for 5 years.
Research continues to show that an aromatase inhibitor is the best hormonal therapy medicine after breast cancer surgery for postmenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer. Still, tamoxifen can be a good choice depending on a woman's unique situation. Side effects and cost may make tamoxifen a better choice for some women. Sequential therapy also may allow some women to get the benefits of Femara without taking it for all 5 years.
When you're deciding on a treatment plan after breast cancer surgery, keep two things in mind:
- Every woman responds differently to treatment. 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, ask 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.