Researchers attribute this to increased awareness of the need for protection from the sun’s harmful ultraviolet (UV) rays.

Ahmedin Jemal, DVM, Ph.D., and colleagues from the National Cancer Institute published these findings on changing patterns of melanoma death rates among whites in the United States in a recent issue of the Journal of the National Cancer Institute (Vol. 91, No. 10).

"Our findings…suggest that mortality from melanoma peaked with the cohort of women born from 1930 through 1950 and for men born from 1935 through 1950," the researchers write. "For the more recent period, mortality is stabilizing in women, whereas it is still rising slightly in men."

Rates of new cases of a disease diagnosed within a certain time period are known as "incidence rates" while rates of deaths from a disease noted during a certain time period are known as "mortality rates."

The authors limited the study to whites because melanoma is about 16 times more common among whites than among African Americans.  Also, increasing melanoma incidence and mortality rates in this country are due to prominent increases among whites but rates have not changed among African Americans.

The leveling off of death rates is likely a result of better awareness of the disease and increases in sun-protection behaviors among women, according to the researchers. For example, surveys found 61 percent of women and 44 percent of men perform skin self-exams and 53 percent of women report using sunscreen routinely versus 36 percent of men.

In older age groups, more deaths from melanoma are seen in both men and women, perhaps as a result of changes in recreation practices that occurred earlier in the 20^th century, when people began spending more leisure time in the sun.

"In contrast, the use of sun-protection methods and early-stage diagnosis could be the most likely reasons for the downturn of mortality rates for cohorts [of Americans] born after 1950," the researchers write, adding that similar trends are seen in other countries, including Australia, Sweden and New Zealand.

The researchers also looked at geographical differences in melanoma rates, comparing data from Atlanta, Detroit, San Francisco and Connecticut. While rates have historically been higher in the South, they found those differences have been changing. Over a 20-year period, melanoma incidence increased more in Northern areas than in Southern locations and more in males than in females.

"These patterns may provide clues as to why mortality rates rose more in the North (low UV-B areas) than in the South (high UV-B areas) and why the rate among females is stabilizing," the researchers write. "Possible reasons for the regional and sex differences in mortality and incidence patterns include differences in sun-protection behaviors and response to campaigns for early detection."

Also, a more mobile population may be equalizing melanoma death rates around the country and making it more difficult to assess geographical differences, according to the researchers.

"It is suggested that migration between geographic areas greatly reduces the sensitivity of methods of assessing cancer risk from environmental exposure, especially when the disease in question has a long latency period," the researchers write. The geographical data used in this study indicates where patients were living at the time of their diagnosis, but does not reflect how long they lived there or where they lived previously.

A Combination of Factors

Overall, the researchers conclude death rates from melanoma in the United States result from a combination of factors, including UV radiation levels in each region of the country, sun-protection habits of each generation of men and women, the mobility of the population and awareness of risk factors and early detection.

Robert Greenlee, Ph.D., program director of cancer surveillance for the American Cancer Society (ACS), says the study’s findings reinforce the recognition that sun exposures early in life – especially intense, intermittent exposures – may be important risk factors for melanoma development later in life. He adds that the news – that death rates are lower among people born since 1950 – is good.

"Such a pattern is expected to eventually result in lower overall mortality rates as [people from] these more recent birth cohorts retain their relatively lower risk as they enter into the older ages, which account for a much greater portion of all cases," Dr. Greenlee says. "This, coupled with the fact that in recent years overall melanoma mortality has stabilized among U.S. white females and is rising only slightly among U.S. white males, suggests that potential overall death rate reductions may not be too far off into the future."

The ACS estimates 47,700 cases of melanoma will be diagnosed in the United States this year, and 7,700 people are expected to die from the disease.