People with scalp or neck melanomas die at nearly twice the rate of people with melanoma elsewhere on the body, including the face or ears, researchers at the University of North Carolina at Chapel Hill have found.
The analysis of 51,704 melanoma cases in the U.S. confirms that survival rates differ depending on where skin cancer first appears. Those with scalp or neck melanomas die at a rate 1.84 times higher than those with melanomas on the extremities, after controlling for the possible influences of age, gender, tumor thickness and ulceration.
"Scalp and neck melanomas patients have a higher rate of death than patients with melanoma anywhere else on the body," said Nancy Thomas, M.D., Ph.D., associate professor of dermatology in the UNC School of Medicine, a member of the UNC Lineberger Comprehensive Cancer Center and the study's senior author. Anne Lachiewicz, a medical student in the UNC School of Medicine, is the lead author of the study.
Thomas recommends that physicians pay special attention to the scalp when examining patients for signs of skin cancer. "Only six percent of melanoma patients present with the disease on the scalp or neck, but those patients account for 10 percent of melanoma deaths. That's why we need to take extra time to look at the scalp during full-skin examinations," she said.
The study helps address a controversy among cancer researchers: whether scalp and neck skin cancer is more lethal primarily because it's diagnosed later than other melanomas. "That was the thinking of a lot of people in the field," Thomas said. But the analysis indicates that the presence of the melanoma on the scalp or neck, in itself, is an indicator of a poorer prognosis.
"We think there's something different about scalp and neck melanomas," Thomas said. "This gives us directions for research to look at tumor cell types in those areas at the molecular level and to see if there are differences. I'm interested in identifying the mutations that drive malignancy."
Thomas, Lachiewicz and their colleagues analyzed data from 13 National Cancer Institute Surveillance Epidemiology and End Results (SEER) Program registries in nine states. Each case represented the first invasive melanoma diagnosed among non-Hispanic white adults between 1992 and 2003.
Patients with scalp or neck melanomas were older (59 years) than patients with other melanomas (55 years), and more likely to be male (74 percent versus 54 percent, respectively). In addition, scalp and neck melanomas were thicker (0.8 millimeters) than melanomas at other sites (0.6 millimeters) and more likely to be ulcerated. Lymph node involvement was also more common in patients with scalp-neck melanomas.
Melanomas on the extremities or on the face or ears had the best prognosis. The five-year melanoma-specific survival rate for patients with scalp or neck melanomas was 83 percent, compared with 92 percent for patients with melanomas at other sites. The ten-year survival rate was 76 percent for scalp or neck melanomas and 89 percent for other melanomas.
Journal reference: Arch Dermatol. 2008;144:515-521.
Study co-authors are Drs. Marianne Berwick and Charles Wiggins of the University of New Mexico.
Funding was provided by the National Cancer Institute and a Holderness Medical Foundation Fellowship to Lachiewicz.
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