ACCELERATED DETECTION WITH PROSPECTIVE SURVEILLANCE FOR CUTANEOUS MALIGNANT-MELANOMA IN HIGH-RISK GROUPS

In 1983 a classification scheme was proposed for patients with atypica l naevi, according to their personal and family history of melanoma an d atypical naevi. To assess the predictive value of these features we undertook prospective surveillance of patients at high risk of primary melanoma. We followed up 116 patients each with 3 or more clinically atypical naevi for at least 5 years. Patients are examined and naevi a re photographed every 3-6 months; lesions showing disturbing change ar e excised for histopathology. Among 85 patients with no personal or fa mily history of melanoma, 5 invasive (level 2 or deeper) melanomas dev eloped during 583 person-years of follow up. The expected number of in vasive melanomas in this population would be 0.054; the increased risk is significant (p < 0.001; relative risk 92 [95% CI 30-216]). There w as a similarly increased risk of new melanoma also among 24 patients w ith atypical naevi plus a history of previous melanoma (observed 2, ex pected 0.022, p < 0.001; relative risk 91 [11-328]). By comparison, no second melanoma developed among 25 patients with previous melanoma bu t a normal naevus pattern during 213 person-years of similarly intensi ve follow-up. The risk of melanoma was highest among 7 patients with a typical naevi and a family history of melanoma (observed 6, expected 0 .009, p < 0.001; relative risk 444 [121-1138]). The median thickness o f surveillance-detected melanomas was 0.75 mm (range 0.40-1.05 mm) in this group. This study shows the value of clinical follow-up of high-r isk patients to detect early thin melanomas.