Latinos in California are increasingly being diagnosed with melanoma, a potentially deadly form of skin cancer, according to a study by researchers at the Keck School of Medicine of USC. The study will appear in the March 1 issue of the journal Cancer but was published early online on Jan. 23.
Since 1988, rates of invasive melanoma have been growing among Latino men, according to Keck School researchers. And more alarmingly, rates of thick tumors in particular�those with a poorer prognosis�have been rising among both Latino men and women.
“When a tumor is thick, that usually means it has been developing for a while,” said lead author Myles Cockburn, assistant professor of preventive medicine at the Keck School. “This is a disease that has a great chance of cure when found early, and routine screening can catch early cases. But in this population, the cancer is becoming more common, and it’s not being caught early enough.
“We believe that efforts must be undertaken immediately to educate Latino communities about how to prevent melanoma: not only reducing sun exposure, but getting regular skin examinations and monitoring their own skin for suspicious lesions.”
Cockburn and his colleagues conducted the study using 1988-2001 data from the California Cancer Registry, the statewide system for recording the occurrence of new cancer cases and cancer deaths. About 140,000 cancer cases and 50,000 cancer deaths are reported statewide each year.
Because nearly 12 million Latinos live in California, the state provides researchers the unique ability to study how cancer affects this group. California also has one of the world’s highest rates of melanoma. These factors allowed the researchers to conduct this first-of-its-kind study.
When they analyzed the 14 years of data, the researchers found something they already suspected: invasive melanoma was increasing significantly among non-Latino whites by more than 3 percent a year. But Latinos’ rates were rising, too�a surprising finding, because most melanoma research has focused on non-Latino whites, who have the highest melanoma risk.
Latino men experienced nearly a 2 percent annual increase in the rate of melanoma over the 14 years. The researchers also observed that invasive melanoma increased among Latinas by less than 1 percent a year, but that increase was not statistically significant.
“What gives us pause is not just the increase in the melanoma rate among Latino men, but the fact that between 1996 and 2001, the rate actually rose by more than 7 percent annually,” Cockburn noted. “That indicates that the problem may be worsening.”
Moreover, the researchers found that among both Latino men and women, thick lesions are becoming far more common than expected.
While tumors thicker than 1.5 mm accounted for about 24 percent of non-Latino white men’s melanomas, they comprised about 35 percent of tumors among Latinos.
“This is critical, because most people diagnosed with thin melanomas will survive 10 years, but as few as 40 percent of people with thick melanomas (more than 4 mm wide) will survive 10 years,” he said. “The best way to improve melanoma survival is to catch melanomas early, while they’re still thin, and that requires regular skin checks.”
Compared to some other common cancers, melanoma is fairly rare among Latinos, but it is growing. Between 1988 and 1989, 121 Latino men and 194 Latino women across the state were diagnosed with invasive melanoma; from 1999 to 2001, 350 Latino men and 448 Latino women across the state were found with the disease.
Although researchers have reported widely on the usefulness of sun-avoidance education and routine screening in preventing melanoma among whites, little is known about the success of prevention techniques among Latinos. Yet, Cockburn noted, the few studies that exist point to a breach in melanoma-prevention practices.
Two studies have shown that Latinos had a poorer awareness of skin cancer risk factors and of their own risk than whites, even though other research has shown that Latinos are just as prone to sunburn as are whites. (Sunburn is a measure of the amount of sun exposure that is enough to produce a response in skin, and probably contributes to melanoma).
And in a recent comparison of skin cancer prevention techniques, more than twice as many non-Latino whites had performed a skin self-exam in the past year compared to Latinos.
The American Cancer Society recommends everyone receive a skin cancer examination by a physician once a year. In addition, the group recommends monthly skin self-exams in front of a full-length mirror to spot any unusual or growing moles or lesions.
Concluded Cockburn: “The word needs to get out about the importance of skin cancer checkups and routine screenings, as well as sun avoidance, in Latino communities.”