NEW YORK (Reuters Health) Oct 01, 2003 - In patients with a history of nonmelanoma skin cancer, selenium use does not prevent basal cell cancer and may actually raise the risk of squamous cell cancer, new research suggests.

Initial results from the Nutritional Prevention of Cancer Trial reported in 1996 showed that selenium use did not influence the incidence of nonmelanoma skin cancer in at-risk individuals. However, the new findings, which are based on three additional years of follow-up, suggest that use of the antioxidant may promote certain cancers.

The current report runs counter to findings from animal studies that indicate a protective effect for selenium and other antioxidants.

The current study, reported in the October 1st issue of the Journal of the National Cancer Institute, involved 1312 patients with a history of nonmelanoma skin cancer who were randomized to receive daily supplementation with selenium 200 micrograms or placebo.

In agreement with the initial results, selenium use was not associated with the risk of basal cell cancer, study author Dr. James R. Marshall, from the Roswell Park Cancer Institute in Buffalo, New York, and colleagues note.

However, use of the antioxidant seemed to raise the risk of squamous cell cancer, the researchers state. Selenium users were 25% more likely to develop the malignancy than nonusers.

"These results must also be considered in terms of the overall impact of supplementation by selenium as a putative chemopreventive agent," the authors note. "Prostate cancer prevention trials presently underway...will help to clarify this overall impact," they add.

Jouranl Nationall Cancer Inst 2003;95:1477-1481.
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