A significant annual increase in invasive melanoma, especially in the occurrence of tumors more than 1.5 mm thick in California Hispanics points to a “developing epidemic” of the cancer in that population, Dr. Myles Cockburn and associates have reported.
The results of their epidemiologic study, combined with studies suggesting that Hispanics don't practice skin self-exam or use sunscreen as often as recommended, mean that physicians should stress these prevention measures in Hispanic neighborhoods (Cancer 2006; doi 10.1002/cncr.21654).
“We recommend that efforts are undertaken immediately to target both primary and secondary prevention messages to Hispanic communities,” said Dr. Cockburn of the University of Southern California, Los Angeles, and his coinvestigators. “This effort should include information on sun avoidance, as well as information on self-screening and recommendations on regular skin checks by a qualified professional.”
The researchers used data from the California Cancer Registry to estimate the annual changes in invasive melanoma among Hispanics and non-Hispanic whites from 1988 to 2001.
During the study period, the incidence of the disease rose about 4% per year for white males, 3% per year for white females, 2% per year for Hispanic males, and nonsignificantly for Hispanic females.
However, the researchers said, the overall 2% annual increase for Hispanic males included an annual increase of 7% for the period of 1996–2001.
Even though the annual increase in melanoma was less in Hispanics than in whites, Hispanics had a far greater incidence of thick lesions at presentation. Tumors thicker than 1.5 mm at diagnosis accounted for 24% of lesions in white men but 35% of lesions in Hispanic men.
In addition, 54% of invasive melanomas among white males were thin (less than 0.75 mm), but only 44% of the lesions were thin in Hispanic men. The incidence of thin tumors diagnosed among whites increased by 5% per year during the study period but increased only nonsignificantly among Hispanics. The incidence of thick tumors among white men increased at 12% per year, compared with a 15% annual increase among Hispanic men.
The increase in thick tumors at diagnosis is troubling because thicker lesions have a substantially poorer prognosis than do thin lesions, the authors wrote.
“These trends have important ramifications for melanoma prevention, because primary and secondary melanoma prevention efforts are focused on non-Hispanic populations,” they said.
The study points up the importance of primary prevention counseling among patients with dark skin, many of whom believe their skin color offers some natural protection from the sun's effects, said Marianne Berwick, Ph.D., an epidemiologist with the University of New Mexico, Albuquerque.
“It is obviously important for Hispanic individuals, just as for all individuals, to look for new or changing spots on their skin—all over their skin, not only on places that are highly sun exposed—because melanoma can occur at any place on the body,” she said in an interview.
“We still don't know enough about sun exposure patterns or the utility of sunscreens in preventing melanoma to offer good advice for Hispanic individuals, but again, as with all individuals, it is important to avoid intense intermittent sun exposure and sunburns,” she said.