If you have hormone receptor-positive breast cancer, hormone therapy with tamoxifen and/or an aromatase inhibitor is a vital part of your treatment.
Aromatase inhibitors are only used to treat postmenopausal women. Premenopausal women should not take aromatase inhibitors. And, women with certain heart problems should not take the aromatase inhibitor anastrozole.
Aromatase inhibitors (such as anastrozole, letrozole and exemestane) have different side effects than tamoxifen (learn more). However, menopausal symptoms are common in women using both aromatase inhibitors and tamoxifen. Your health care provider can help you treat many of the side effects.
Figure 5.11 lists some possible side effects of aromatase inhibitors.
| Figure 5.11: Side Effects of Aromatase Inhibitors |
| Common |
- Fatigue
- Hot flashes and night sweats
- Joint and muscle pain
- Loss of bone mineral density
- Sleep problems
|
| Uncommon or rare |
- Bone fractures
- Depression
- Dizziness
- Hair thinning
- Headache
- Heart problems
- Increased blood pressure
- Increased cholesterol
- Nausea and vomiting
- Osteoporosis
- Swelling in the arms and legs
- Vision problems
|
Adapted from selected references [55-60].
|
Side effects of aromatase inhibitors versus side effects of tamoxifen
Like tamoxifen, aromatase inhibitors often cause menopausal symptoms such as night sweats and hot flashes. Aromatase inhibitors do not cause blood clots or uterine cancer, which are rare health effects with tamoxifen. They also have lower rates of vaginal bleeding and discharge and endometrial cancer compared to tamoxifen. However, aromatase inhibitors have higher rates of joint pain, muscle pain and heart problems than tamoxifen [55-60].
Learn about methods to ease menopausal symptoms.
Aromatase inhibitors and loss of bone mineral density
Aromatase inhibitors cause bone mineral density loss, which leads to higher rates of osteoporosis and bone fractures compared to tamoxifen [60]. You can help strengthen your bones through regular exercise, getting enough calcium and vitamin D (your health care provider can tell you if you are getting enough calcium and vitamin D) and not smoking [61].
Some medications may also help prevent osteoporosis. Your provider may prescribe drugs called bisphosphonates or the drug denosumab to help maintain bone mineral density while you are taking aromatase inhibitors.
Although mostly a concern for people with metastatic breast cancer who take higher doses of bisphosphonates or denosumab, these drugs can cause severe bone, joint and muscle pain [61-63]. If you have any of these symptoms, report them to your health care provider right away. In rare cases, a serious jaw bone disorder called osteonecrosis may occur. It is important to have a dental exam prior to starting treatment with bisphosphonates [39].
Long-term side effects
More time is needed to assess the long-term risks and benefits of aromatase inhibitors.
Updated 04/17/12
