Risk of developing multiple primary cutaneous melanomas in patients with the classic atypical-mole syndrome: a case-control study

The classic atypical-mole syndrome (CAMS) and/or a history of malignant melanoma (MM) increases the risk for multiple melanomas. Case notes of 118 CAMS and 173 control patients, each with a history of MM, were reviewed for the occurrence of second primary MMs. The mean (+/-SD) age at diagnosis of the first MM was 38.8 +/- 12.8 and 48.9 +/- 14.7 years (P < 0.001) for CAMS cases and controls, respectively. Thirty-two of 118 CAMS and 18 of 173 controls developed second primary MMs, for a cumulative 10-year life-table risk of 35.5% and 17.0%, respectively (P < 0.0001). The mean number of months from the time of diagnosis of the first to the second MM was 33.9 +/- 41.8 and 58.6 +/- 57.3 months for the CAMS and controls, respectively (P = 0.08). In both cohorts the second MMs were significantly thinner, compared with the first MMs. The relative risk (RR) for developing second MMs for CAMS patients was 3.2. The RR for the CAMS cohort compared with a matched population from the United States Statistics, Epidemiology. End Results data base was 337, and for the controls, the RR was 84. All patients with MMs are at significant risk for developing multiple MMs: the risk is greater for patients with CAMS. Periodic total cutaneous examinations are indicated for life in an attempt to identify new MMs when they are thin.