Having More Moles Doesn’t Necessarily Increase Cancer Risk

A new study draws question to the risk of melanoma associated with moles.
A new study draws question to the risk of melanoma associated with moles.  Getty Images

If you think not having many moles on your body means you have less risk of melanoma, you're wrong. A new study from Harvard reverses this widespread misconception, suggesting that fewer moles may actually mean greater risk of the deadly skin cancer. Of 566 melanoma patients, 66 percent had fewer than 20 moles on their body, while 73 percent had zero atypical moles, a common sign of the disease.

"Moles are still an important risk factor for melanoma, and total mole count is still something to consider," says lead researcher Alan Geller. "However, as this study shows, it's a big mistake to only be checking for melanoma on people with a lot of moles. The last thing we'd want is for a doctor say, 'Oh, you have so few moles; you don't have anything to worry about.' "

Moles or no moles, just by being a man gives you plenty to worry about. Men are about 50 percent more likely to have melanoma than women — and twice as likely to die from the disease. And if you're white, you're 20 times more likely to have melanoma. Also, unlike many cancers, melanoma isn't an old man's disease. It's not uncommon among guys in their 40s, 30s, or even 20s.

Like all skin cancers, the best way to prevent melanoma is to avoid frying in the sun. "A lot of melanomas can be prevented by very vigilant sun protection throughout your whole life," says Geller. "Make sure you use sunscreen on all exposed skin, seek shade when you can, and wear a shirt to cover your back, where one-third of melanomas in men occur."

But let's be real: Most of us get caught in the sun unprotected from time to time. That's why, to spot melanoma before it manifests, it's crucial to constantly survey your skin. Because while mole count may not be as indicative of melanoma risk as once thought, mole characteristics remain very telling.

There are often clear signs, such as an oblong shape or changing color, that a mole may be melanoma. "Melanoma usually writes its message on your skin for you to see," Geller says. "But you have to understand what to look for." To tell a normal mole from an unusual one, he advises following the ABCD rule:

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  • A is for asymmetric. Healthy moles are usually fairly symmetric. You shouldn't see much difference between one side and another. If it's a wacky shape, it may be melanoma.
  • B is for border irregularity. Moles should be round or oval. If the border is jagged or uneven, or if you notice that a border has changed, get it checked out.
  • C is for color. Most healthy moles are beige or brown. If it becomes dark brown, black, or multicolored, that's concerning.
  • D is for diameter. If a mole is wider than pencil-head eraser, see the doc.  

"A mole doesn't have to have all four of these characteristics to be problematic — only one," says Geller. But don't just wait until you happen to spot something sketchy. "Get to know your skin right now, and keep a vigilant eye on it," says Geller. "Have your partner check your back, head, and other tough-to-see spots, and don't be afraid to ask your doctor for a full-body skin check."