Cutaneous malignant melanoma in Australia, 1989.

OBJECTIVE

To describe the characteristics of cutaneous malignant melanoma in Australians in 1989. DESIGN AND DATA: Descriptive analysis of all invasive melanomas reported to State or Territory cancer registries in 1989.

MAIN OUTCOME MEASURES

The age, sex and State or Territory of residence of affected individuals, and the topography, morphology and thickness of the melanoma.

RESULTS

The age-standardised incidence rates of melanoma were 30.2 and 23.9 per 100,000 males and females respectively; the highest rates were observed for the male trunk (11.7 per 100,000) and female lower limbs (8.8 per 100,000); the most commonly specified morphology was superficial spreading melanoma, followed by nodular melanoma and lentigo malignant melanoma. Fifty-two per cent of melanomas of known thickness were thinner than 0.76 mm, with females having proportionally more thin melanomas than males, and males having twice the rate of melanomas thicker than 3 mm. Melanoma rates in northern latitudes were approximately double those further south.

CONCLUSIONS

Distinct patterns of melanoma incidence by latitude and body site confirm the role of sunlight exposure in melanoma aetiology. Females often have thinner melanomas than males, which is reflected in their better prognosis. People living closer to the equator more often have level 1 (in situ) and thin invasive melanoma, probably related to increased awareness of melanoma risk with decreasing latitude. The collection of melanoma data would be improved if pathologists' reports routinely included melanoma site, morphology, level and thickness. All registries should collect data on level 1 melanomas to help evaluate early melanoma detection programs and to continue surveillance of the Australian skin cancer epidemic.