Extended Use of Aromatase Inhibitors After Five Years

Extended adjuvant use means that your doctor can prescribe hormonal medication for longer than five years. After five years of tamoxifen, many physicians recommend an additional five years of the aromatase inhibitor Femara. This "extended use" of hormonal therapy is based on a clinical study called MA–17.

In this study of more than 5,000 women, half took Femara and half took a placebo (dummy pill) for five years. Before the study, they had all taken tamoxifen for four and a half to six years after their initial treatment for their original cancer.

The study showed that Femara reduced the risk of recurrence by almost twice as much as the placebo. The study was stopped earlier than expected so that all the women could have the chance to take Femara for extended use.

If you have advanced (metastatic) breast cancer and have already been switched from tamoxifen to an aromatase inhibitor, you should continue taking it as long as the cancer under control.

If the cancer comes back and progresses while you're on your current medication, your doctor will probably recommend that you try another therapy. Your doctor may suggest a different aromatase inhibitor, or a course of Faslodex (chemical name: fulvestrant). Tamoxifen can also be used, if the aromatase inhibitors have stopped working. This only makes sense if you've never taken tamoxifen before or if you took it a long time ago—but not if tamoxifen also has stopped working.