The epidemiology of cutaneous malignant melanoma in Nova Scotia
AL Howlett | RA Dewar | SF Morris
BACKGROUND: Since 1993, the annual increase in cutaneous malignant melanoma (MM) incidence has been one of the highest for all cancers registered in Canada, with the leading rate in Nova Scotia (NS). The purpose of the present study was to document the pathological and epidemiological data on MM cases found in NS.
PATIENTS AND METHODS: All MM cases identified by the Nova Scotia Cancer Registry from January 1998 to December 2002 were evaluated. The five-year survival outlook, by major prognostic factors, was also determined. In addition, the annual incidence and mortality rates from 1972 to 2002 were computed.
RESULTS: Between 1998 and 2002, 925 MM cases were recorded. The age-standardized incidence rate for males and females in this period was 19.2 and 16.1 per 100,000 respectively. Men 65 years of age or older had the highest age-specific rate. The most common MM had a Breslow's depth of less than 1.0 mm (61.9%) and was Clark's level II (34.9%). There was no significant seasonal variation noted in the time of diagnosis. Survival analyses indicated that sex, age, tumour location and thickness were significant independent predictors. Despite the increase in incidence, there have only been modest changes in the annual mortality rate.
CONCLUSION: The incidence of MM in NS increases with age, and is nearly double for men 65 years of age or older, compared with women in the same age group. Thin melanomas on the extremities of young females have the best prognosis in NS, which is similar to other parts of the world. Incidence appears to be unrelated to season. Public health interventions are necessary to reduce the burden of this disease.