Sun Spotted

Using data from the California Cancer Registry, researchers find increasing rates of skin cancer among Latino men and women.

by Alicia Di Rado

Keck School of Medicine of USC epidemiologists have a wake-up call for all Latinos who think they are safe from melanoma: Think again.

Latinos in California are increasingly being diagnosed with this potentially deadly form of skin cancer, according to a study in the March 1 issue of the journal Cancer.

Since 1988, rates of invasive melanoma have been growing among Latino men in the state. And more alarmingly, rates of thick tumors—those with a poorer prognosis—have been rising among both Latino men and women.

“When a tumor is thick, meaning more than 4 millimeters deep, that usually means it has been developing for a while,” says lead author Myles Cockburn, Ph.D., 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. USC health experts head the Los Angeles County Cancer Surveillance Program, which tracks the same data specifically for the local region.

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 14 years of data, the researchers found something they already suspected: Invasive melanoma was increasing significantly among non-Latino whites (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. Researchers 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 seven percent annually,” Cockburn notes. “That indicates that the problem may be worsening.”

Moreover, the researchers found that among both Latino men and women, thick lesions were 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 will survive 10 years,” he says.

Compared to some other common cancers, melanoma is fairly rare among Latinos, but it is growing. In 1988 and 1989, 121 Latino men and 194 Latina women across the state were diagnosed with invasive melanoma; from 1999 to 2001, 350 Latino men and 448 Latina women in 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 notes, 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 sufficient 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 to monthly skin self-exams in front of a full-length mirror to spot any unusual or growing moles or lesions.

Concludes 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.”

 

REASONS FOR SUSPICION

Whether called moles or beauty spots, tiny bits of pigmented flesh are commonly found on the skin. Moles are usually evenly brown, tan or black and can be either flat or raised and shaped like circles or ovals. Most often, they are the size of a pencil eraser or smaller.

Appearing as early as childhood, once moles arise, they usually stay the same shape and color. If moles begin to grow or change shade, though, that should be a warning sign to visit a dermatologist to rule out melanoma, a potentially lethal form of skin cancer. People of any ethnicity may develop melanoma.

Physicians use the easy-to-remember code of “ABCD” to remind people of suspicious characteristics to watch for in a mole. ABCD includes the first letter of the following four factors:

Asymmetry: The mole is unevenly shaped, with one half not matching the other.

Border irregularity: The mole’s edges are irregular, ragged or blurred.

Color: The mole may contain two or more different colors, including the usual brown and black as well as potentially red, white or blue.

Diameter: The mole is wider than 1Ú4 inch—though physicians are increasingly finding melanomas that are smaller in size.

For more information on melanoma, visit the American Academy of Dermatology Web site at www.aad.org and click on “Dermatology A-Z”.