Caucasians living in tropical or sub-tropical climates, such as the American Southwest, equatorial Africa, Hawaii or Australia, have the highest incidence. Obviously, exposure to ultraviolet light, particularly that leading to sunburn, is strongly suspected as a cause.
There are about 15 cases among each 100,000 Caucasians in California or Arizona, while 30 cases are found per 100,000 Caucasians in Hawaii and Australia. Blacks, brown-skinned people and Orientals in the same regions have a much lower incidence.
Even in the Northeast, the incidence is more than 10 per 100,000, up from 8 per 100,00010 to 15 years ago. Melanoma is becoming a major concern in countries of the Northern hemisphere such as Sweden, Finland and England, where the incidence is increasing for reasons that are not entirely clear.
Melanoma is most common in people in their forties to sixties and is rare before puberty. An increasing number of young adults with primary melanomas are being seen, however; many of them had episodes of intense sunburn in their childhood. A tumor known as clear cell sarcoma , arising in the soft tissues such as muscle or the tissue under the skin, is made up of the same type of malignant melanocytes as adult melanomas. Children and adults can have this form.
Eye melanomas are most common in fair-skinned people living in sunny climates, suggesting that dark glasses completely blocking ultraviolet rays should be worn by blue-eyed people when out in bright sunlight.
• Among Caucasians, red-haired people with very fair complexions are at the highest risk, followed by blond,
