Incidence rates of skin cancer in Townsville, Australia

Abstract

Worldwide, incidence rates of skin cancer are increasing alarmingly in populations of predominantly Caucasian origin. A prospective population-based survey, set up to collect epidemiological information on all excised and histologically confirmed skin cancers, started in Townsville, Australia (population of 127,000) in December 1996. Data on the anatomical distribution of skin cancer has been collected using a detailed body map. Estimations of type-specific and site-specific incidence rates were age-standardized according to world standard population. Site-specific incidence rates were adjusted for surface proportion of the body site and are given per 100,000 body units. Between December 1996 and December 1997, a total of 3,536 patients with 5,945 histologically confirmed skin cancer lesions were recorded. Age-standardized incidence rates of basal cell carcinoma were 2,058.3 for men and 1,194.5 for women, 1,332.3 for men and 754.8 for women for squamous cell carcinoma, and 49.1 for men and 41.7 for women for cutaneous melanoma (CM). Site-specific incidence rates of non-melanocytic skin cancer were extreme on sun-exposed areas of the face, whereas site-specific incidence rates of CM were highest for neck, posterior trunk and face. Less exposed body sites, such as unexposed upper limbs or thighs, showed reduced incidence rates for all types of skin cancer. Tropical North Queensland has the world's highest incidence rates of skin cancer of all types. Site-specific incidence rates demonstrate that highly sun-exposed body sites are at high risk of developing skin cancer and provide, therefore, strong indirect evidence for the causal relationship between sun exposure and skin cancer.