Study Identifies Risk Factors For Multiple Melanoma Skin Cancer

In 2005, there will be an estimated 62,000 new cases of invasivemelanoma and an estimated 7,600 deaths due to melanoma in the UnitedStates, according to background information in the article. Melanoma isthe fifth leading cancer in men and the sixth leading cancer in womenin the United States. The incidence of melanoma continues to rise atabout 3 percent per year in the United States, with an estimatedlifetime risk for an individual of 1.4 percent. This increasingincidence puts a larger portion of the population at risk not only forone primary melanoma but also for subsequent primary melanomas.

Cristina R. Ferrone, M.D., and colleagues from Memorial Sloan-KetteringCancer Center, New York, conducted a study to identify the incidenceand characteristics of patients at risk of developing multiple primarymelanomas (MPM). The study included 4,484 patients diagnosed with afirst primary melanoma between January 1, 1996, and December 31, 2002.

The researchers found that 385 patients (8.6 percent) had 2 or moreprimary melanomas, with an average of 2.3 melanomas per MPM patient.Seventy-eight percent had 2 primary melanomas. For 74 percent ofpatients, the initial melanoma was the thickest tumor. Fifty-ninepercent presented with their second primary tumor within 1 year.Twenty-one percent of MPM patients had a positive family history ofmelanoma compared with only 12 percent of patients with a singleprimary melanoma (SPM). Thirty-eight percent of MPM patients haddysplastic nevi (DN; atypical moles) compared with 18 percent of SPMpatients.

The estimated cumulative 5-year risk of a second primary tumor for theentire cohort was 11.4 percent, with almost half of that risk occurringwithin the first year. For patients with a positive family history ordysplastic nevi, the estimated 5-year risk of MPM was significantlyhigher at 19.1 percent and 23.7 percent, respectively. The moststriking increase in incidence for the MPM population was seen fordevelopment of a third primary melanoma from the time of second primarymelanoma, which was 15.6 percent at 1 year and 30.9 percent at 5 years.

"Patients with a positive family history or a history of DN are atsignificantly greater risk of developing MPM and should be enrolled inmore intensive dermatologic surveillance programs. This high-risksubset of patients should also be further characterized genetically tofurther elucidate the biology and etiology of melanoma," the authorsconclude.