Hormonal therapy effectively reduces the risk of hormone-receptor-positive, early-stage breast cancer coming back (recurring) in postmenopausal women. Hormonal therapy medicines are usually taken for 5 years after the main treatment is completed. A study found that the risk of breast cancer coming back was even lower when hormonal therapy was taken for 3 more years, for a total of 8 years of hormonal therapy.
A treatment given after the main treatment is called adjuvant therapy. Hormonal therapy given for more than 5 years after the main treatment is called extended adjuvant therapy. In this study, tamoxifen was given for 5 years as adjuvant therapy, which is standard.
The women in the study who got extended adjuvant therapy received Arimidex (chemical name: anastrazole), an aromatase inhibitor, for 3 years after the 5 years of tamoxifen. The women who took tamoxifen and Arimidex had a 38% lower risk of the breast cancer coming back than the women who took only tamoxifen.
Other research has shown a similar benefit for extended adjuvant therapy using Femara (chemical name: letrozole), another aromatase inhibitor.
Giving hormonal therapy for a total of 8 years after surgery (extended adjuvant hormonal therapy) isn't used routinely right now. But if the results from this study are repeated, it may be an option to consider.
As with any breast cancer treatment, the benefits should be weighed against the side effects and risks. Some women who take aromatase inhibitors may have painful bone and muscle aches.
If you're a postmenopausal women taking hormonal therapy medicine after surgery for breast cancer, you might want to talk to your doctor about these research findings. Together, you can decide whether extended adjuvant hormonal therapy might be a good option for you as you do all that you can to lower the risk of the breast cancer coming back.
Visit the breastcancer.org Hormonal Therapy section to learn more about tamoxifen, aromatase inhibitors, and adjuvant therapy.