Calcium, Vitamin D Supplements May Pose Risks for Men With Prostate Cancer

Although they're standard treatment for men with prostate cancer who are taking hormonal therapy, calcium and vitamin D supplements may do more harm than good, according to a new study.

Men who undergo hormone-depletion therapy for prostate cancer are at risk for osteoporosis, but the supplements do not prevent this bone loss and may actually boost patients' odds for heart disease and aggressive prostate cancer, research from Wake Forest Baptist Medical Center suggests.

"Calcium and/or vitamin D supplementation to prevent loss of bone mineral density in these men seems so logical that no one had questioned whether it works," study co-author, Mridul Datta, a postdoctoral fellow at Wake Forest Baptist, explained in a hospital news release.

"It wouldn't be so bad if there simply was no obvious benefit," added the study's lead author, Gary Schwartz, a prostate cancer epidemiologist at Wake Forest Baptist. "The problem is that there is evidence that calcium supplements increase the risk of cardiovascular disease and aggressive prostate cancer, the very disease that we are trying to treat."

In the study, the researchers reviewed guidelines for calcium and vitamin D supplements as well as the results of 12 clinical trials of these supplements involving almost 2,400 men with prostate cancer. All of the men were receiving hormone-deprivation therapy. The researchers also examined the men's bone mineral density before and after treatment.

According to the study, the men undergoing hormone therapy for prostate cancer who took the recommended daily doses of calcium and vitamin D supplements lost bone density.

The researchers also pointed out that increased dietary calcium is associated with a greater risk for aggressive prostate cancer and heart disease.

"The wake-up call of these findings," concluded Datta, "is that the presumption of benefit from calcium and vitamin D supplements that have been routinely recommended to these men must be rigorously evaluated."

The study's authors said more research is needed to confirm their findings and investigate the possible risks of calcium and vitamin D supplementation, particularly heart disease and prostate cancer.

One expert agreed that more study is needed.

The study authors "say that traditional approaches use too little calcium and/or vitamin D, but that as one increases the doses there are other risks, such as cardiovascular events," noted Dr. Louis Potters, a prostate cancer specialist and chair of radiation medicine at North Shore - LIJ Health System, in New Hyde Park, N.Y. "So that the trade-off for treating osteoporosis is associated with other risks."

Potters stressed that "not all men with prostate cancer need hormone therapy, only those with high-risk or advanced disease. And for those men, they need to have a discussion with their physician about the risks of these medications and how best to perhaps mitigate some of those risks."

The study was published online in the July issue of The Oncologist.