The results appear in the April issue of the journal Archives of Dermatology.
The study's senior author, Dr. Nancy Thomas, associate professor of dermatology in the UNC School of Medicine, urges physicians to pay special attention to the scalp when examining patients for signs of skin cancer.
The study helps address a controversy among cancer researchers about whether scalp and neck skin cancer is more lethal mainly because it's diagnosed later than other melanomas - in part because hair covers it up.
"That was the thinking of a lot of people in the field," Thomas says.
But the study points to the presence of the melanoma on the scalp or neck, in itself, as an indicator of a poorer prognosis.
"We think there's something different about scalp and neck melanomas," Thomas continues. "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.
On The Early Show Saturday, New York dermatologist Lisa Airan said she asks some of her patients to wet their hair, making it easier to examine their scalps. If you have a regular hairdresser, you can ask him or her to keep an eye on your scalp and watch for potential problems, she added.
The danger signs of skin cancer can be summarized with a simple "ABCD" guide, Airan says.
A Asymmetry: One clear danger sign is a mole or lesion that's irregularly shaped, not symmetrical. Most moles - the kind you usually don't have to worry about - are more or less round. So keep an eye out for odd shapes.
B Border: Again, the danger sign is irregularity. If the edges of a mole or lesion are smooth, you have less to worry about. If they're uneven, that's a concern.
C Color: Most normal moles are uniform in color, some even shade of brown. But varied shades of brown, tan, or black are often the first sign of melanoma and something to pay close attention to.
D Diameter: A useful rule of thumb is that a mole smaller than a pencil eraser is probably not cancerous. But if it starts changing, growing larger, that's a worry.
Any significant combination of these four things - Asymmetry, Border, Color and Diameter - and you should see your doctor.
To keep track of these things, you should do a monthly self-examination, Airan urges, saying, "Paying attention to your skin on a regular basis is the best way to catch melanoma before it becomes a serious threat. Checking it once a month will make you aware if there's a change. Photographs are also useful - I don't know how common this is, but when I have patients with lots of moles, I send them to a photographer who takes full-body photos. That makes it much easier to keep track of changes."
If you're concerned that you might be developing melanoma, go right to your dermatologist, Airan stresses: "Sometimes people get worried about things that seem abnormal, but aren't really a problem. Then, the doctor can reassure you. But if it's questionable, a dermatologist can do a biopsy: remove the mole or lesion and send it to a laboratory for examination. That's really the only way to be absolutely sure - you can't make a definitive diagnosis, just by looking. And so I say that if you are really worried about something, you should urge the doctor to do a biopsy. The bottom line is: Do a self-exam once a month and consult a dermatologist if you see something.
Who's most at risk for melanoma? Says Airan: fair-skinned people, people with a family history of skin cancer, and people who work out in the sun or otherwise have a lot of sun exposure. But - this is important - anyone can get melanoma.
To protect yourself, use a high-number sunblock, re-applied frequently. The active ingredients in sunblock only last a few hours. And the amount you apply is important, too. An eight-ounce bottle of sunblock is good for about eight applications. At the end of the summer, if you still have the same bottle of sunblock you started with, you aren't using enough! Other obvious ways of protecting yourself from the sun include wearing a hat and staying under a canopy when sitting outdoors. There is also specially-treated clothing that's very effective at blocking the sun.
But be aware: You can over-protect yourself from sunlight, and that it can leave you short of Vitamin D. The body makes Vitamin D when exposed to the sun, and we all need Vitamin D. If you stay out of the sun's rays too much, it's easy to correct your Vitamin D level: Just take a vitamin supplement.
For more information visit the University of North Carolina at Chapel Hill Web site.