Estrogen, Bone Loss, and Chemotherapy

Chemo can cause loss of bone density

Osteodensitometry of the hip with an osteoporosis
Osteodensitometry of the hip with an osteoporosis. Getty Images/BSIP/UIG

If you've recently finished chemotherapy for breast cancer, you might want to ask your family doctor or your oncologist to send you for a bone-density scan. This is a painless test that will show whether your bones have lost density, or thinned, during your treatments. Bones will lose density due to lower levels of estrogen, a hormone that helps build up and protect your bones.

How Chemo Can Cause Bone Thinning

Chemo that includes cyclophosphamide, methotrexate, and fluorouracil (CMF) is the combination which is most likely to cause estrogen suppression. Post-chemo medications, such as Tamoxifen and Raloxifene also help to lower estrogen levels and are important as a follow-up for patients who had estrogen-receptor positive (ER+) tumors.

Estrogen levels drop naturally during menopause, and during chemotherapy, many pre-menopausal women experience "chemo-pause" (monthly periods cease or become irregular). Regardless of whether your estrogen levels drop due to natural or chemical menopause, bone health becomes an important thing to discuss with your healthcare team.

Actions You Can Take After Treatment

You can ask for a blood test which will determine your estrogen levels after you've completed treatment for breast cancer. However, the results may vary greatly, depending on your age, your general health, and how much time has passed since your treatment was completed. Ovaries produce estrogen, and it may take from 6 months to 2 years for the ovaries to recover if they are going to be as productive as before treatment. Talk this over with your gynecologist or family doctor, to get help deciding on the timing of this test, in order to get the most accurate results for you.

If your ovaries do start working again (producing estrogen, stimulating monthly periods), then your bones can regain their natural density and strength on their own. If you are indeed in menopause (no monthly periods for 3 months or more, a pregnancy test that has a negative result, and an FSH (follicle-stimulating hormone) blood test of at least 30 milli-internationals units per milliliter), then you may need to take medication to rebuild bone.

You can also help your body to strengthen bones by adding calcium with vitamin D to your daily multivitamin, along with weight-bearing exercise. Tai Chi is a great, gentle way to exercise and regain your balance and bone strength. Walking, or using a treadmill or stair machine will also help. If you're up to it, take low-impact exercise classes to help you regain your strength, stamina, and confidence. Remember to drink plenty of fluids and eat a balanced diet, all of which will assist you to the best recovery.

More Tips to Help Your Bones

Here are two more tips on keeping your bones fit after treatment for breast cancer: stop smoking, and limit alcohol use. Smoking contributes to osteoporosis (bone density loss) and although it is hard to quit, you will reduce your risk of recurrence of breast cancer, as well as lower your risk of other cancers. Heavy use of alcohol also causes osteoporosis, as well as causing your body to increase estrogen levels in your blood.

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