Vitamin D, calcium supplements may prevent lethal skin cancer
MedWire News: Women with a nonfatal form of skin cancer may be able to reduce their risk for developing a lethal form of the disease by taking supplements of vitamin D and calcium, US scientists say.
However, they warn that their findings should be considered preliminary and admit it is too early to recommend the use of these supplements in order to prevent skin cancer.
The intriguing findings come from an analysis of data from a large clinical trial known as the Women's Health Initiative (WHI). Conducted among 36,282 women aged 50-79 years, the WHI compared the effect of taking daily vitamin D and calcium supplements on different aspects of health.
The study's primary purpose was to test whether these supplements improved the women's bone density and prevented colorectal cancer. But the volume of information collected has also allowed researchers looked at the effect of supplements on the women's likelihood of developing other, less common diseases.
The latest report, by Jean Tang (Stanford University, California), compared rates of skin cancer between women who took supplements and those who took a sugar pill (placebo). The dose of vitamin D was low, at just 400 IU per day, while the dose of calcium was 1000 mg per day.
Importantly, neither the women themselves nor the study investigators knew who had been given the supplements and who had been given a placebo until after the study had finished, 7 years later.
Writing in the Journal of Clinical Oncology, Tang and co-authors reveal that the chance of developing melanoma - the most deadly form of skin cancer - was halved among women who took vitamin D/calcium supplements compared with women who took a placebo.
However, this was only the case among a specific group of women - namely, those who had previously been diagnosed with a more common and less severe form of skin cancer, known as non-melanoma cancer. Examples of non-melanoma skin cancers include basal cell and squamous cell cancer.
Commenting on the findings, Tang said: "In preventive medicine, we want to target people most at risk for the disease. If you previously had a non-melanoma skin cancer, calcium plus vitamin D might reduce your risk of the more deadly melanoma."
However, she added a note of caution, warning that the study was not specifically designed to test the impact of these supplements on skin cancer. "These results spur us to do more studies," she said.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Joanna Lyford