Malignant melanoma in Cape Town, South Africa.

Abstract

There is a world-wide increase in the incidence of cutaneous malignant melanoma among white people. Absence of accurate population-based data on the incidence of melanoma in South Africa prompted a study to determine the incidence, anatomical sites and pathological details of melanoma in Cape Town. In a prospective study from 1 January 1990 to 31 December 1995, all the histopathology reports of melanoma presenting in a geographically defined area of Cape Town, were actively retrieved from every pathologist practising in this area. The data evaluated included information on age, sex, ethnic group and location of residence. Details of melanoma comprised body site, Clark level of invasion, Breslow thickness in millimetres and histogenetic type. The histology slides were reviewed by a panel in those cases where the recorded information was ambiguous or incomplete. A final number of 595 reports of primary invasive cutaneous melanomas in white people was analysed. Of these 50.3% were men and 49.7% women. The overall age-standardized incidence rate was 24.4 per 100,000 per annum (27.5 for men and 22.2 for women). There was no change in the incidence rate over the study period. Most melanomas in both sexes (74% of women and 71% of men) were < 1.5 mm Breslow thickness. Results of this study indicate a high incidence rate of melanoma in white South Africans, comparable with that in Australia, which demands urgent preventive health measures.