Are You at Risk for Broken Bones if You Are On an Aromatase Inhibitor?

This is the second post on bone health and why it is so important for breast cancer survivors.  In the first post, we covered the causes of bone loss, who is at risk, and what you can do to keep your bones strong. To read that post, just click here, and then you can come back to this one.

As you were going through breast cancer treatment, you knew to ask about the side effects of the chemotherapy and radiation, how long it would take to recover from surgery, and when you would be able to get back to a normal schedule.

But, as most of you have found out, the treatment can have subtle and long-term effects that you might not have thought of. Bone loss is one of those effects that can be overlooked. But you can’t blame treatment completely. Bone loss happens to us all as we age even if you are not a breast cancer survivor.

How do you know whether or not you have strong bones?  The easiest and most accurate way to know your bone strength is with a bone density test (also known as a DXA or DEXA scan). These tests are quick, easy, and painless and you can learn more about them by clicking here. The test will give you a T-score.  This score shows you how your bone density compares to the bone density of a healthy 30-year old.  A score of -1.0 or higher (meaning less negative) is normal.  If your score is between -1.0 and -2.5 it means that your bones are on the weak side which is a condition called osteopenia. Osteopenia means that your bones are weaker than normal, and you might benefit from some medications in addition to a healthy diet, vitamin D, calcium, and weight-bearing exercise to strengthen your bones. Scores of -2.5 or below mean you have osteoporosis and are at risk for fractures even from minor falls.

Why are breast cancer survivors at increased risk for bone loss? Most survivors are post-menopausal.  Either they were diagnosed after menopause or treatment made them menopausal.  The drop in estrogen levels that comes with menopause increases bone loss. In addition, many women with hormone positive breast cancer will have to take aromatase inhibitors as part of their treatment for several years. While these aromatase inhibitors are critical for reducing the risk of breast cancer recurrence, they also have some side effects. One of those side effects is increasing bone loss.

Patients who are placed on aromatase inhibitors should have a bone density test as described above. In addition, you should be taking calcium and vitamin D and incorporating some resistance and weight-bearing exercises into your routine. If your bones are weak enough based on the bone density test, you may need some medications.  Most commonly, oncologists start with bisphosphonates or denosumab to prevent further bone loss.

Recently a joint position statement was published on breast cancer and the prevention of bone loss for patients taking aromatase inhibitors.  A “joint position statement” is an agreement among several expert groups with an interest in this topic.  This statement included treatment recommendations for women who are getting started on aromatase therapy with regard to the prevention of bone loss. You can read the full statement here. Basically, the recommendations come down to this:

• If you are receiving breast cancer treatment that will cause bone loss, you should have a bone density test
• If your T-score is higher than -2.0 (meaning less negative) and you have no additional risk factors, you should take calcium, vitamin D, and exercise
• If your T-score is less than -2.0 (meaning more negative), then you should take calcium, vitamin D, exercise, and receive either denosumab or a bisphosphonate
• See the graphic below

 Hadji P, Aapro MS, Body J-J, et al. Management of Aromatase Inhibitor-Associated Bone Loss (AIBL) in postmenopausal women with hormone sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO, IMS, and SIOG. Journal of Bone Oncology. 2017;7:1-12. doi:10.1016/j.jbo.2017.03.001.

Many breast cancer survivors are at increased risk for bone loss due to their post-menopausal status and hormonal treatment. A simple bone density test can tell you how strong your bones are. Based on this test and what hormonal treatment you are receiving, your oncologist can determine how best to protect your bones from further loss.