Fosamax and breast cancer

Last December, many news outlets were reporting the latest finding to come from the 2002 Women’s Health Initiative in articles that trumpeted the finding that women who were taking Fosamax and other bisphosphonates for their bones had 32% fewer breast cancers than women who weren’t. At first blush, the idea that you could prevent two of the most frightening conditions that affect post-menopausal women — osteoporosis and breast cancer — with a single medication would seem to be a breakthrough of tremendous importance. I wanted to know more. So I looked at what little information is available about the study — there’s not very much, just an abstract from the meeting where the study was presented and various news reports — and consulted with Dr. Dixie Mills, Medical Director of the Dr. Susan Love Research Foundation, to make sure I understood clearly what the findings meant.

My findings only confirmed my initial suspicions that popular media outlets were blowing the significance of this study out of proportion. I’d like to caution women not to take the headlines at face value. Why? For four reasons:

1. First, bisphosphonates like Fosamax, Actonel, and Boniva stop the activity of bone-building osteoblasts, which I feel (and science supports) could, over time, make bone brittle and more prone to fracture. Unless you’re at very high risk for breast cancer, trading lower risk of breast cancer for the risk of hip fracture would just not be helpful.

2. The information in the study wasn’t part of a clinical trial — it was drawn from the Women’s Health Initiative, which was never intended to study whether osteoporosis drugs affect breast cancer rates. “Observational” data like this is never as meaningful as data from a well-designed double-blind, randomized clinical trial because there is no way to make sure you’re comparing people and circumstances that are fundamentally alike. It’s as though you’re talking about “citrus fruit” without being able to say whether you’re looking at oranges, grapefruits, lemons, or limes!

3. Even if it’s true that these drugs have the happy side effect of limiting breast cancer it doesn’t change the fact that they also have many other unhappy side effects that make them very difficult, if not impossible, for women to tolerate. These side effects include serious digestive disorders and the increased risk of esophageal cancer.

4. The finding reported in the news consisted of “relative risk” data — that is, they compared the risk statistic of women on the drugs who got cancer to the risk of women not taking drugs who got cancer. This approach obscures the fact that in absolute terms, if you treated 100 women for 10 years with these drugs, you’d prevent only 1 incidence of breast cancer — and statistically speaking, that’s a lot of cost to women’s health, both physical AND financial, for a very small benefit!

5. Finally, as Dr. Mills pointed out, along with the decrease in invasive cancer that was so broadly discussed in the media was a less widely reported increase in the incidence of ductal carcinoma in situ (DCIS), a non-invasive, milder form of cancer that is nevertheless an important health concern for women.

All of these factors mean that this study’s findings really are very weak, so until someone undertakes a large, well-designed clinical trial that shows the same results, I think the hoopla is a bit premature.

I know there are better ways — natural ways — that women can both improve bone health and lower their risk of cancer of any kind (not just breast cancer) than using bisphosphonates. Here are four areas you can explore if you want to know more:

• Look into getting your Vitamin D status checked. Vitamin D plays a multitude of roles in our health, including helping us maintain strong bones and cancer prevention.

• Learn more about chronic inflammation, which has been implicated in a wide range of health problems — including some forms of cancer.

• Eat an alkaline diet rich in vegetables and fruits, which offer a range of cancer-fighting and –preventing antioxidants.

• Obtain all the 20 key bone building nutrients in adequate doses. All of these nutrients also help build and maintain immune strength.

References:

Bankhead C. SABCS: More evidence that bisphosphonates prevent breast cancer. Medpage Today, December 10, 2009.

Chlebowski RT, Chen Z, Cauley JA, et al. 2009. Oral bisphosphonate and breast cancer: Prospective results from the Women’s Health Initiative (WHI) (abstract). Paper presented at the San Antonio Breast Cancer Symposium, December 10, 2009, San Antonio, TX.