Among women with a history of non-melanoma skin cancer (such as basal cell carcinoma or squamous cell carcinoma), vitamin D and calcium supplements may reduce the risk of melanoma. These results were published in the Journal of Clinical Oncology.
Of the more than one million new diagnoses of skin cancer each year, roughly 68,000 involve melanoma. More than 8,000 people die of melanoma each year in the United States. What makes melanoma so dangerous is that it is more likely than other types of skin cancer to spread (metastasize) to other parts of the body.
Although advances have been made in melanoma treatment, the disease continues to be challenging to control. As a result, prevention of melanoma remains an important goal.
Vitamin D is important for bone health, and some research suggests that it may also reduce the risk of certain types of cancer. A role for vitamin D in cancer prevention has not yet been firmly established, however, and research on this topic continues. Vitamin D can be produced in the skin in response to ultraviolet B (UVB) radiation from the sun or obtained from dietary sources. Few foods naturally contain large amount of vitamin D, but vitamin D can be obtained from fatty fish such as salmon, fortified foods such as milk, and dietary supplements.
To explore the relationship between vitamin D and skin cancer, researchers evaluated information from Women’s Health Initiative trial of calcium and vitamin D. The trial enrolled roughly 36,000 women between the ages of 50 and 79.
Study participants took either daily calcium and vitamin D supplements (with a daily dose of 1,000 mg of elemental calcium and 400 IU of vitamin D3) or placebos. Previous reports from this study indicated that calcium and vitamin D supplementation did not reduce the risk of colorectal cancer or breast cancer.The current report focused on both melanoma and non-melanoma skin cancer.
- Overall, calcium and vitamin D supplementation did not affect the risk of melanoma or non-melanoma skin cancer.
- In the subgroup of women with a history of non-melanoma skin cancer, those in the vitamin D and calcium group had a 57% reduction in risk of melanoma. There were 10 melanoma cases in the calcium and vitamin D group and 24 cases in the placebo group.
These results suggest that vitamin D and calcium supplementation may reduce the risk of melanoma in women with a history of non-melanoma skin cancer. Subgroup analyses such as this one can be prone to bias, however, and these results cannot be viewed as definitive. The lead researcher on the study is planning to conduct additional studies on vitamin D and cancer prevention.
Talk with your healthcare provider if you have questions about your vitamin D status or need for additional vitamin D. In addition, keep in mind that although sun exposure can produce high levels of vitamin D, organizations such as the American Academy of Dermatology do not recommend sun exposure as a source of vitamin D because of the link between sun exposure and skin cancer. Dietary supplements can provide an identical form of vitamin D without the skin cancer risk.
 Tang JY, Fu T, LeBlanc E et al. Calcium plus vitamin D supplementation and the risk of nonmelanoma and melanoma skin cancer: post hoc analyses of the Women’s Health Initiative Randomized Controlled Trial. Journal of Clinical Oncology. Early online publication June 27, 2011