Epidemiology of melanoma

Melanoma incidence and morality rates are increasing in most countries thro ughout the world where they are being recorded. The annual incidence rates have increased in the order of 3-7% in fair-skinned populations in recent d ecades. The mortality rates have increased at a rate lower than for inciden ce. This has been attributed to educational programs designed to improve th e early detection of melanoma, as the treatment of melanoma has not changed substantially in recent decades. There has been a decrease in the thicknes s of melanoma with an increasing proportion of thin melanomas at diagnosis. Causation of melanoma is a combination of constitutional risk factors of w hich skin colour is the major factor. The presence and number of common acq uired and dysplastic melanocytic naevi is also a major constitutional risk factor in fair-skinned people. The only environmental risk factor that has been shown consistently is exposure to sunlight, particularly large doses o f sunlight sufficient to cause sunburn in childhood that will be remembered many years later. However, recreational activity leading to sunburn in adu lthood is also associated with risk. To date, no other environmental factor s have been shown epidemiologically to be clearly associated with risk of m elanoma. Recent epidemiological data from some studies suggesting that ther e is an increased risk of melanoma in sunscreen users requires further expl anation.