Genetic and environmental influences in the development of multiple primary melanoma

Objectives: To identify risk factors and the prognosis associated with the development of multiple primary melanoma (MPM). Design: Case-comparison studies of subjects with MPM and single primary mel anoma. Sequencing of CDKN2A in germline DNA. Setting: Population-based study of patients with invasive melanoma in Scotl and between 1979 and 1996. Patients: For mortality studies, 108 patients with MPM and 216 single melan oma controls matched for age, sex, site, and tumor thickness. For risk fact or studies, 48 patients with MPM and 48 single melanoma controls matched as above. For CDKN2A analysis, a sample of 23 subjects with MPM. Results: The development of MPM was found not to be an independent prognost ic factor. The risk of MPM was greatest in those with a family history of m elanoma, with large numbers of benign nevi, and the presence of clinically or histologically atypical nevi. Germline mutations of CDKN2A were present in 6 of 23 patients with MPM and in 5 cases consisted of the base pair subs titution Met53Ile. Conclusions: The importance of MPM should be addressed in melanoma follow-u p protocols. Those patients at greatest risk can be identified by a family history of melanoma and their mole pattern. Germline mutations in CDKN2A oc cur in both familial and sporadic MPM and further studies are required to d etermine the value of analysis of this gene in melanoma surveillance. Patie nts should be informed that the development of MPM does not adversely affec t their prognosis.