Epidemiology of skin cancer in the mature patient.

Epidermal cancers include keratinocyte cancer, melanocyte cancer, and Merkel cell carcinoma. These cancers account for the vast majority of new cancers diagnosed in Australia, North America, and Europe. Keratinocyte cancer is the most common epidermal cancer and accounts for 7 out of 8 new cancers diagnosed in Australia. Melanoma and Merkel cell carcinoma are less common than keratinocyte carcinoma but are more important causes of mortality in Australia. Keratinocyte cancer has also been demonstrated to be a marker of cancer-prone phenotype. Risk factors for epidermal cancer include intrinsic and environmental factors, in particular exposure to ultraviolet radiation and advanced age. Actinic keratosis has an approximate prevalence of 79% of men and 68% of women between 60 and 69 years of age, and has a low risk of malignant transformation into squamous cell carcinoma. Basal cell carcinoma is the most common malignancy in Caucasians worldwide, with the incidence increasing by 2% per year in Australia. Squamous cell carcinoma is the second most common epidermal cancer, with an incidence of approximately 1035 or 472 per 100,000 person-years in men and women, respectively. Primary risk factors for both basal cell carcinoma and squamous cell carcinoma include light skin color, UV radiation exposure, and chronic immunosuppression. Although the rate of melanoma is increasing, the mortality in Australia is reducing and is currently 9%. The overall incidence of melanoma in Australia is approximately 50 cases per 100,000 persons (62 for men and 40 for women). Keratinocyte carcinoma and melanoma are risk factors for developing further skin cancer and primary malignancy. This contribution reviews the incidence, prevalence, and risk factors associated with the development of epidermal cancer and premalignant epidermal neoplasia.