Skin cancer common, more aggressive in ethnic patients

Chicago - Dermatologists need to keep their vigilance up for skin cancer when treating patients from darker-skinned ethnic groups, according to Hugh M. Gloster, Jr., M.D.

"We see skin cancer more frequently than we expect to in people of color, and, when we do, cancers are typically more aggressive than those seen in white patients," he said in his presentation here at the American Academy of Dermatology's Academy '05. Dr. Gloster is an associate professor of dermatology at the University of Cincinnati, where he is the director of dermatologic surgery.

Educating patients

"Sunlight is not as important a risk factor for skin cancer in ethnic patients as in white patients," he says. "For example, squamous cell and melanoma in ethnic patients occurs in anatomic sites that are unlikely to be exposed to the sun, while in white patients the lesions appear in exposed areas."

Also, while basal cell carcinoma is the most common skin cancer in white patients, squamous cell carcinoma and melanoma are more common in patients of color. However, basal cell carcinoma does occur in ethnic patients, and, when it does, it is in sun-exposed sites.

"Therefore, we have to educate even darker patients about sun protection," he says.

Squamous cell carcinoma

Although squamous cell carcinoma is the second most common type of skin cancer in white patients, it is the most common type in patients of African and Asian Indian descent. In those ethnic groups, the lesions typically appear in the lower extremities, while in whites, the head and neck are typically involved.

"Squamous cell carcinoma develops in areas of chronic scarring and inflammation, such as leg ulcers and areas where there's been chronic inflammation, such as in lesions of lupus erythematosus," Dr. Gloster says. "Unfortunately, when squamous cell carcinoma arises in the scars of ethnic patients, 20 percent to 40 percent of the lesions will spread, compared to 1 percent to 4 percent of those developing in sun-exposed areas in whites. Squamous cell carcinoma is associated with a 17 percent to 30 percent mortality rate in ethnic patients. Any time an ethnic patient has a non-healing ulcer or scar, the dermatologist should biopsy it to screen for cancer."

The aggressive nature of squamous cell carcinoma in ethnic patients could be due to the delayed diagnosis.

"Nobody's looking for it," Dr. Gloster says. "They also get more aggressive subtypes."

Basal cell carcinoma

Basal cell carcinoma is the second most common skin cancer in patients of African descent. As with all patients, this cancer is associated with chronic sun exposure and is no more aggressive in blacks than in whites.

"However, the lesions look different," Dr. Gloster says. "They are dark brown in people of color, while they tend to be pearly and translucent or red with pearly borders in white patients."

In patients of Asian descent, especially those with lighter skin, such as Chinese or other East Asian patients, basal cell carcinoma is also the most common skin cancer. However, in darker Asian patients, squamous cell carcinoma is more common.

In patients from Spanish-speaking countries, the most common skin cancer subtypes vary, depending on the ethnic makeup of the country of origin. For example, patients from Argentina may be more susceptible to basal cell carcinoma, because they are more likely to have lighter skin. However, those from Central America or Mexico may be less susceptible to skin cancers that are influenced by ultraviolet exposure, Dr. Gloster says.