The Challenge of Balancing Hormone Therapy and Bone Health

By Keith I. Block, MD

As you probably know, hormonal therapy is considered standard treatment for women - and men - with estrogen receptor-positive breast cancer, and tens of thousands of patients, predominantly women, receive this treatment each year. The most widely used option for premenopausal women—first introduced in the 1970s—is Tamoxifen, which blocks the activity of estrogen by binding to the hormone’s receptor site. In more recent years, for postmenopausal women, Tamoxifen has been upstaged by aromatase inhibitors (AIs), drugs that block production of estrogen. (AIs generally follow two years of Tamoxifen for premenopausal women.) Both AIs and Tamoxifen, used either separately or together in sequence comprise an essential conventional strategy for curbing the risk of breast cancer recurrence. And some recent data suggests that AIs may be more effective in preventing early relapses.

Despite the therapeutic usefulness of AIs, these drugs are not without a downside. AIs have toxic effects on the bones and heart. Indeed, the common finding in all studies to date that have compared AIs with Tamoxifen is an increased risk of bone loss, and an increased risk of fractures in women taking AIs. AIs are basically amplifying a problem that is already quite rampant in postmenopausal women: Immediately after menopause, women typically lose bone at an annual rate of 3 to 5%, mostly due to a decrease in circulating estrogens [Source: May-June 2011 issue of CA: A Cancer Journal for Clinicians]. The use of AIs further accelerates this process, and yet at least three out of every four survivors with osteoporosis may go undiagnosed by their healthcare providers, as reported in a 1 October 2005 issue of Cancer.

There are several strategies to consider when receiving AIs. The first is to incorporate a bone-building program that includes a high-quality calcium supplement (either calcium citrate or calcium hydroxyapatite) along with vitamin D3. This combo has been shown to reduce the rate of bone loss and decrease the rate of fractures. However, the likelihood of bolstering bone health is far greater when women include other bone building nutrients such as magnesium, potassium, vitamin C, vitamin K, carotenoids, and several B vitamins. Though boron (a component of many bone building formulas) may be helpful in trace amounts, it can enhance the activity of estrogen and thus is best minimized.

Epidemological studies indicate that people on predominantly vegetarian diets have the strongest bones over the long term. Though dairy is a good calcium source, the research suggests that eating more dairy does little to curb osteoporosis or promote bone health. One suggested reason for this is that increased intake of animal protein leads to a urinary excretion of calcium. Thus, the more dairy and other proteins consumed, the higher the risk for calcium loss. I recommend a plant-based diet centered around an abundance of vegetables – emphasize broccoli, collards, kale and other cruciferous and leafy green vegetables, as these tend to have higher calcium levels than other vegetables – as well as berries, cherries and grapes. These fruits provide several health benefits and can help reduce inflammation, which we know plays a role in osteoporosis (One of the major contributing factors to osteoporosis in women is withdrawal of estrogen during menopause. Human and animal experiments have implicated pro-inflammatory cytokines as key biochemical contributors to the accelerated bone loss at menopause). Other health promoting foods like soy, nuts and seeds contain highly bio-available calcium as well. Daily weight-bearing exercise and avoidance of caffeine, alcohol, refined sugar, and high-phosphorous junk foods can be extremely helpful as well.

To counteract bone loss, many oncologists recommend the use of bisphosphonates like Fosamax, Boniva® (generic name: ibandronate) and Zometa® (zoledronic acid). These drugs have been shown to significantly increase bone mass and reduce the risk of fractures. Their effectiveness would likely be further improved by the addition of a vegetable-rich diet, along with the supplement advice I outlined above. In fact, I believe it is essential that women who elect to take bisphosphonates also include these diet and lifestyle recommendations.

Given the widespread problem of osteoporosis, it comes as no surprise that bisphosphonates are currently among the most-prescribed drugs in America. The downside is that these drugs have been linked with joint pain, allergic reactions, GI distress and other symptoms. On rare occasions, they can even promote a terrible condition called osteonecrosis of the jaw—that is, the death of tissue in the jaw bone.

Against this grim-sounding backdrop, many breast cancer survivors with ongoing bone loss want to know whether it’s really necessary for them to continue with bisphosphonates. Unfortunately, there is not a simple answer to this question. Nonetheless, to continue taking AIs without bisphosphonates on board requires very cautious monitoring by your physician. Even with such monitoring, there remains a substantial risk of bone loss. The other option is to switch from AIs back to Tamoxifen, which could actually improve bone health over the long term. If this strategy is chosen, I would recommend routine gynecologic exams and including both nutrients and herbs that are synergistic with Tamoxifen, as well as some that counter formation of blood clots. This option and topic deserves further attention, and will be considered in a future blog.

For more information on The Block Center for Integrative Cancer Treatment, visit BlockMD.com.