(RxWiki News) Breast cancer survivors can have ongoing health challenges after they’ve beaten "The Big C." Many are on medications that block estrogen, the hormone that drives most breast cancers. These medicines also increase the risk of osteoporosis (brittle bones) and increase the risk of fractures.
A new review of studies found that the recommended daily doses of calcium and vitamin D supplements didn't help breast cancer survivors maintain healthy bones.
The therapies that boost the risks for brittle bones are also known to increase the risk of heart disease. And there is some evidence that calcium and vitamin D supplements add to the heart disease risks.
dailyRx News spoke about these dilemmas with a breast cancer expert who is an integrative oncologist.
"Make time for exercise every day."
Gary G. Schwartz, PhD, a cancer epidemiologist at Wake Forest Baptist Medical Center, and Mridul Datta, PhD, a postdoctoral fellow at Wake Forest Baptist, conducted the review.
These researchers examined the effect of calcium and vitamin D supplements on preventing the loss of bone mineral density, a measure of bone strength, in breast cancer survivors.
Medications that block estrogen including tamoxifen (brand names Nolvadex, Soltamox, Tamofen, Tamoxen) and aromatase inhibitors such as Arimidex (anastrozole), Aromasin (exemestane) and Femara (letrozole) have been shown to increase the loss of bone mineral density in numerous studies.
To battle brittle bones, breast cancer survivors are commonly advised to take 500 to 1,500 milligrams of calcium and 200 to 1,000 IU of vitamin D daily.
The reviewed trials measured bone mineral density at the beginning and end of the study to measure the effect of supplementation. The researchers examined the results of 16 trials involving both pre- and postmenopausal women.
The researchers found no trials that looked at both calcium and vitamin D supplementation versus no supplementation.
According to the authors, the commonly prescribed dosages of these supplements "...were inadequate to inhibit bone loss in pre- and postmenopausal women with breast cancer."
The bad news doesn’t stop there, unfortunately. “Breast cancer therapies increase the risk of cardiovascular disease, the primary cause of death in women with breast cancer,” the authors wrote. “Besides an increased risk of cardiovascular disease from breast cancer treatments, supplemental calcium intake may also increase the risk of cardiovascular disease, although this remains controversial.”
So what’s a breast cancer survivor to do? dailyRx News spoke with Brian D. Lawenda, MD, an integrative oncologist and clinical director of Radiation Oncology at 21st Century Oncology in Las Vegas.
“It is time for us to question the effectiveness of only recommending calcium and vitamin D supplements in this population,” Dr. Lawenda said. “Clearly, this preventive strategy is inadequate to reduce the loss of bone mineral density. But I would certainly not throw the baby out with the bathwater. It is very possible that without supplementation, the rate of loss of bone mineral density might be significantly worse.”
Dr. Lawenda, who is the founder of IntegrativeOncology-Essentials.com, continued, “The take home point for my patients should be that calcium/vitamin D supplementation is not enough, and that more needs to be done if they want to maintain their bone mineral density. As an integrative oncologist, I counsel patients on the importance of incorporating resistance exercises to help maintain bone density.”
“Additionally,” Dr. Lawenda continued, “I recommend to my patients that we keep their 25-OH vitamin D levels greater than 40 ng/ml, since studies suggest that lower levels are associated with increased loss of bone mineral density. Achieving levels of 25-OH vitamin D that are greater than 40 ng/ml (I prefer 60-80 ng/ml in my practice) often requires significantly higher doses of vitamin D3 supplementation than were employed in the studies reviewed in this analysis.
“To reduce the potential increased risk of cardiovascular disease with calcium supplementation, studies suggest that by taking vitamin K2 (along with the calcium and vitamin D3) the calcium is directed into your bones and not into the walls of your blood vessels,” he said.
Dr. Lawenda, who was not involved in this study, added, “I also spend a great deal of time in my integrative oncology visits helping patients address a variety of important lifestyle factors such as chronic stress, unhealthful diets, systemic inflammation, excessive caffeine intake and tobacco use, as these are known risk factors for osteoporosis and osteopenia [decreased bone mass].
“Finally, there are numerous medications that may need to be considered in these patients, particularly those who are postmenopausal and are taking certain medications for breast cancer that are known to cause a more rapid loss of bone mineral density (i.e., aromatase inhibitors, Tamoxifen),” Dr. Lawenda concluded.
The findings from this study were published in the journal Critical Reviews in Oncology/Hematology.
The research was supported by the Comprehensive Cancer Center of Wake Forest University Cancer Control Traineeship. No conflicts of interest were reported.