How to Spot Skin Cancer

Medically Reviewed

You might already know how to use your ABCDEs to spot suspicious moles that could be signs of skin cancer. A = asymmetry (one half of your mole isn’t the same as the other), B = border (borders are uneven), C = color (various shades of uneven color), D = diameter (larger than 6 mm) and E = evolving (noticeable changes occurring over time).

But did you know that using numbers also helps in evaluating your skin cancer risk? According to a 2015 United Kingdom study, having more than 11 moles— called “nevi in medical terms—on one arm is associated with an increased risk of melanoma, a potentially deadly type of skin cancer. This isn’t an entirely new premise—doctors already know that having more than 50 to 100 moles on the entire body is associated with an elevated melanoma risk. But counting moles on only one arm may allow primary care physicians to quickly assess a patient’s risk.

Self-examination is also a critical step, especially for people at high risk as well as former skin cancer patients. A separate study from Rutgers Cancer Institute of New Jersey reports that less than 15 percent of patients who have had malignant melanomas perform routine, whole-body self-exams to check for new or recurring cancers.

Seventy-two percent of 176 patients (average age, 61) surveyed performed a partial-body check, but that’s not enough, say experts. Patients should be using full-length mirrors, handheld mirrors and, whenever possible, another person to aid in checking hard-to-see areas of the body. When asked why they didn’t routinely perform thorough skin self-exams, most patients cited a lack of awareness and knowledge of what to look for.

The American Cancer Society recommends that all adults perform a head-to-toe skin self-exam once a month. If you’re unsure of how to perform one, ask your doctor to show you. Your doctor can also tell you whether you are at increased risk for skin cancer and should undergo annual physician- directed, full-body skin screenings. And if you’ve had melanoma, ask your doctor for a personalized plan to check for recurring or new cancers—and then be diligent about following it.