Breast Cancer Breakthrough
What is letrozole?
When a woman is diagnosed with breast cancer, she often has the tumor surgically removed and may undergo radiation and/or chemotherapy. Many then take a drug named tamoxifen to prevent a recurrence. The drug has been very effective, but it should only be given for five years. After that it doesn't help and may actually do harm. Now we think the new drug may pick up where the old one leaves off, reducing the chance of a relapse by 43 percent.
How does the new drug work?
Letrozole, marketed as Femara and taken in pill form once a day, inhibits the enzyme aromatase that is active in producing estrogen in postmenopausal women.
Why is it important to reduce estrogen?
Estrogen is the fuel that drives breast cancer.
But doesn't a woman's estrogen level drop after menopause?
Yes. In women who are still menstruating, the ovaries create estrogen, so when the cycles stop, the levels in the blood do drop substantially. But the bodies of postmenopausal women also produce estrogen using the enzyme aromatase. Estrogen levels in the breasts themselves are very similar in pre-and postmenopausal women.
Can a young breast cancer patient be treated with letrozole?
No, it cannot be used by itself on premenopausal women.
Should women who are on tamoxifen continue to take it for five years or switch to letrozole?
Tamoxifen is very effective. Women should not stop their therapy midstream.
Is letrozole right for all women who have taken tamoxifen for five years?
Each woman should discuss her own situation with her doctor. The treatment depends on a number of factors, including the size of the original tumor, its aggressiveness and whether the lymph glands were involved.
What are the drawbacks?
The main concern is that reducing estrogen may lead to thinning bones and osteoporosis. We still don't know if letrozole will cause other side effects.
Are diet and exercise important?
Many breast cancers could be prevented with lifestyle changes. So women should watch their weight, exercise and cut down on alcohol.
Are there any other promising new drugs?
Yes, there are a number of prevention studies going on worldwide. One is a very large study of tamoxifen versus a similar drug called raloxifene. The women in this study have never had breast cancer before but may have an increased genetic risk.
Are mammograms still the gold standard of detection?
Clearly, they aren't perfect. But until new methods are found, the use of conventional approaches—including self-examination—has to continue.