The melanoma epidemic: res ipsa loquitur.
Many have debated whether or not we are in the midst of a melanoma epidemic. Some facts are clear and helpful to this debate, while others are less clear. The incidence and mortality of melanoma have increased over the last several decades, but the incidence has risen faster than the mortality. The incidence has risen 3%-7% on average over several decades and even more rapidly among Caucasian men and the elderly. In the U.S., the incidence in men is higher than in women after the age of 40, and the difference between men and women increases from age 40 until the end of life. The incidence in the U.S. has risen most rapidly among in situ and localized lesions, but distant and regional disease have increased as well. Among localized disease, in the U.S. from 1988-1997, all stages increased by comparable amounts. This strongly argues against the idea that the increase in incidence of melanoma is only due to early detection of thin lesions or biologically benign lesions, at least during the time period studied. On the other hand, early detection of thin lesions may well account for lower increases in mortality than incidence and improvements in survival. Survival has increased from approximately 60% in the 1960s to 89% in recent years. Improvements in survival appear to be related to earlier diagnosis, rather than an improvement in survival of a given stage. Studies consistently point to a major role for UV light exposure as the most important risk factor for those individuals with a phenotypic susceptibility. Public health efforts aim at primary and secondary prevention strategies. Primary prevention strategies attempt to prevent people from developing melanoma, primarily through avoiding exposure to UV light. There is a particular emphasis on avoidance of UV light exposure in childhood and young adulthood, when it appears the risk is greatest. When strict avoidance cannot be adhered to, sunscreens have been logically recommended. Secondary prevention strategies include screening campaigns and educational campaigns. Many of these strategies appear promising but require further rigorous testing. The melanoma epidemic has arisen for a variety of reasons including: a true increase in melanomas of malignant behavior, a particularly high increase in localized and in situ lesions, and an increase in the number of biopsies performed, which may have resulted in an increased detection of less aggressive lesions. The contribution of possible changes in the diagnostic criteria for melanoma to the increased incidence remains unknown.
Beddingfield
Frederick C
FC
Department of Medicine, Division of Dermatology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA. fbeddingfield@mednet.ucla.edu
D004196:Disease Outbreaks; D006801:Humans; D008545:Melanoma / Q000453:epidemiology* / Q000517:prevention & control*; D012307:Risk Factors; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D014481:United States / Q000453:epidemiology