Cutaneous (skin) melanoma begins in cells known as melanocytes, which produce the pigment that gives skin its color. Previous studies have evaluated the recurrence of melanoma among patients already diagnosed with the disease; most have estimated that less than 4 percent of them will develop additional tumors in the year following diagnosis, according to background information in the article.
Linda Titus-Ernstoff, Ph.D., Dartmouth Medical School, Lebanon, N.H., and colleagues assessed the frequency of and risk factors for recurring cancer among 354 New Hampshire residents with a first diagnosis of cutaneous melanoma. Participants completed a 40-minute telephone interview, during which they answered questions about medical history, demographics, eye and hair color, sun exposure and whether their skin tanned, burned or freckled in the sun. They then underwent a skin examination, during which a physician identified and catalogued benign and atypical moles. Atypical moles have at least three of the following features: a diameter larger than 5 millimeters, redness, an irregular or ill-defined border, a variety of colors or a portion that is flat.
By examining pathology records, the researchers found that 20 (6 percent) of the participants developed an additional melanoma within one year of diagnosis and 27 (8 percent) developed an additional melanoma within two years. Sixty-three percent of those who developed additional tumors and 37 percent of those who did not had at least one atypical mole. The more atypical moles an individual had, the more likely he or she was to develop additional melanomas--three or more atypical moles indicated four times the risk. Lifetime history of sun exposure did not appear to influence the risk of recurring melanoma. However, those with a history of sunburn were less likely to develop a second melanoma than those without, a finding that "must be viewed cautiously," the researchers write. Those who are predisposed to develop multiple melanomas may be less susceptible to sunburn than those with one melanoma, or they may be more likely to avoid sun exposure. "In any case, the association should not be construed as suggesting that sunburn protects patients with melanoma from developing additional tumors," the authors continue.
"The importance of studying risk for additional primary tumors within a defined population-based study group is underscored by our findings," they conclude. "These findings, which indicate a higher frequency of second primary melanomas than suggested by previous studies, also underscore the importance of close surveillance of patients with melanoma."
(Arch Dermatol. 2006; 142:433-438. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This project was supported by a grant from the National Cancer Institute, Bethesda, Md.