MALIGNANT-MELANOMA IN ITALY - RISKS ASSOCIATED WITH COMMON AND CLINICALLY ATYPICAL MELANOCYTIC NEVI

Background: Most epidemiologic studies on risk factors for cutaneous m elanoma have been performed in predominantly fair-skinned populations. Objective: Our purpose was to assess by means of a case-control study the importance of common melanocytic nevi (CMN) and clinically atypic al nevi (CAN) as risk factors for cutaneous melanoma in a Mediterranea n population. Methods: One hundred six patients with invasive cutaneou s melanoma and 109 population control subjects were included in the st udy. Ah subjects were younger than 70 years of age and were residents of the Florence area. Results: The adjusted odds ratios obtained by ex act conditional analysis, accounting for age, sex, place of birth, and residence, were 2.6 (95 confidence interval [CI], 1.0 to 6.7) for 10 to 30 CMN, and 22.3 (CI, 4.8 to 215) for more than 30 CMN (chi(2) for trend, 25.41;p < 0.001), 2.9 (CI, 1.2 to 7.5) for large nevi, and 8.4 (CI, 2.2 to 31.4) for CAN. Tendency to freckle resulted in a twofold i ncrease in risk (odds ratio, 2.2) (CI, 1.0 to 5.2). The relative risk associated with a large number of CMN was statistically significant af ter adjustment for all other variables. When adjusted for the number o f CMN, none of the other variables showed a statistically significant increased risk. Conclusion: A large number of CMN represents the most important risk factor for cutaneous melanoma in the Italian population . The presence of large nevi and CAN did not result in an increased ri sk when the number of CMN was considered.