Chronic exposure to arsenic, which can be measured in toenail clippings, seems to be associated with an elevated risk of melanoma skin cancer, investigators report.

“There has been little research investigating the link between arsenic and cutaneous melanoma, although arsenic has been associated with increased risk of nonmelanoma skin cancer.” Dr. Lara E. Beane Freeman, of the National Cancer Institute, Bethesda, Maryland, and colleagues write in the October issue of the American Journal of Epidemiology.

The researchers looked for any association between melanoma and environmental arsenic exposure in 368 Iowa residents with melanoma and 373 with colorectal cancer. The participants completed a mailed survey, and submitted toenail clippings for analysis.

Arsenic accumulates in hair and nails and provides an indication of long-term exposure. The team analyzed the clippings for arsenic content by incinerating them in a graphite oven and measuring the proportion of elements by atomic absorption spectrometry.

Patients with the highest toenail arsenic concentrations were more than twice as likely to have melanoma as those with the lowest concentrations The risk was not related to skin color, skin type or history of sunburn.

“The association we observed with arsenic is not known to have been previously reported,” the researchers note. “Therefore, the findings warrant confirmation.”

SOURCE: American Journal of Epidemiology, October 2004.