Despite campaigns in the US promoting early detection of melanoma, the proportion of the most aggressive and deadly form (thick melanomas) remains the same, according to an article in the June issue of Archives of Dermatology.

Incidence and mortality of melanoma in the US have risen steeply from 1969 to 1999, according to background information in the article, with a disproportionately greater increase in men 65 years and older. Melanoma mortality is strongly associated with the thickness of the primary lesion.

Marie-France Demierre, MD, and her American colleagues analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database to determine trends in distribution of thin and thick melanoma from 1988 to 1999. The number of new melanoma cases in a three-year period increased 60 percent from 1988-1991 (n=9,132) to 1996-1999 (n= 14,575).

The proportion of thick melanomas (at least two millimeters thick) remained relatively stable during the 12 study years. Nodular melanoma (an aggressive type) comprised 9 percent of all recorded cases but 34 percent of thick melanomas. In contrast, superficial spreading melanoma (a more common type) was almost uniformly diagnosed as an early tumor, mostly presenting as thin melanoma.

"A substantial number of thick melanomas in the United States are of the nodular subtype," the authors concluded. "...Apparently the current ABCD of melanoma, the core of the early-detection educational programs, may not suffice to permit the early detection of nodular melanoma. For example, it is apparent that targeting middle-aged and older men is warranted. This observation has been supported by the Institute of Medicine, which conceded that 'clinicians and patients should continue to be alert to the common signs of skin cancer-with a particular emphasis on older white males and on melanoma.'

Finally, as we gain greater understanding of melanoma carcinogenesis and molecular alterations leading to the development of biologically aggressive thick melanomas, other strategies such as chemoprevention may play a role in reducing the risk of developing thick melanoma and decreasing mortality from melanoma."