Cancer Hormone Drugs and Bone Loss: Beware Hidden Damage

Patient Expert

Did you know hormone therapy to prevent breast cancer recurrence can lead to bone loss? Here's how to approach this serious issue.

Breast cancer treatment can be a long process - if you've been through it, I'm preaching to the choir here, right?

Not only does treatment feel long, with surgery and its aftermath, radiation and/or chemotherapy, and dealing with potentially devastating side effects. It IS long - add hormone therapy to the mix, and you're talking years of active treatment.

And that's just if everything goes right.

By the time you get to the long, drawn-out end game of anti-recurrence drugs - a.k.a. hormone therapy - you're a side effects expert. You've already been through surgery's pain, chemo's nausea, and radiation's burns; hormone therapy feels like a piece of cake.

Taking a daily aromatase inhibitor (AI) ­- Arimidex, Femara, or Aromasin - is simple. Just pop that pill in the morning, and you're done. Yes, about 50% of women report bothersome joint pain; but for the remaining 50%, the experience is thankfully uneventful.

Which, since your doctor will probably recommend you continue hormone therapy for 10 years, is a good thing.

There's just one problem - a potentially devastating but silent side effect, one that can change the course of your life: bone loss, which can lead to osteoporosis.

So, why risk hormone therapy?

If you're in the 75% of women whose breast cancer is hormone-receptive, your cancer needs estrogen to grow. Hormone therapy effectively and efficiently blocks cancer cells from getting the estrogen they need; aromatase inhibitors actually prevent your body from manufacturing the hormone.

Lowering your estrogen level is great for preventing a breast cancer recurrence - but tough on your bones. Estrogen is the prime hormone our bodies use to regulate bone growth, the ongoing process of bone breakdown and subsequent buildup. Without estrogen, the process falls out of balance; women taking an AI lose bone mass twice as fast as normal, healthy women.

What does all this mean, in real-life terms? If you're taking an AI, you're 27% more likely to develop osteoporosis; and 21% more likely to suffer a non-traumatic fracture (i.e., a rib fracture caused simply by coughing, or a wrist broken by swinging a tennis racket). And if you have additional risk factors, your risk is even greater.

Not a pretty picture, right?

Don't just sit and worry. There are things you can do right now to help slow down bone loss.

First, if you haven't already, get a DEXA scan. This test will give you a baseline picture of your bones right now - so you can track how much strength they lose over time.

Second, speak to your doctor about other osteoporosis risk factors. If you have a family history of osteoporosis; or if you have a small, light frame, you're at greater risk, even before factoring in the effect of your AI.

You can't control how your cancer drugs are affecting your bones; but there are other things you CAN control, including the following:

-Smoking and drinking. If you're a smoker, here's another reason to quit: smoking helps reduce bone density. If you drink, do so moderately; the less you drink, the more you lower risk of bone loss (and breast cancer recurrence, as well).

-Calcium and vitamin D. Make sure you're getting enough of both of these bone-enhancing substances. Ask your doctor to check your levels; if they're low, take a supplement.

-Exercise. Weight-bearing exercises - those that give your bones the controlled stress they need to grow - are especially critical. Think jogging, dancing, step classes, and other active pursuits, ones that involve quick movements.

In addition, strength training (weight-lifting) not only helps your bones, it strengthens your core, making you less likely to fall (and potentially break a hip, or your back).

Sources

Hamel, PJ. "Breast Cancer and Osteoporosis: Beware the Connection." Http://www.healthcentral.com/breast-cancer/c/78/112231/osteoporosis/. May 22, 2010.

Hill, Jane. "Bone Basics." Cure, July 1, 2014, 24-27.

See more helpful articles:

Beyond Common Risk Factors: Hidden Causes of Osteoporosis

Calcium: 10 Different (and Tasty) Sources

Hip Fracture: Don't Go There

Breast cancer survivor and award-winning author PJ Hamel, a long-time contributor to the HealthCentral community, counsels women with breast cancer through the volunteer program at her local hospital. She founded and manages a large and active online survivor support network.