Watch for Mole Changes - The ABCDE Rule for Early Detection of Melanoma

Not Overlooking a Change in a Mole Can Save Your Life

Moles (melanocytic nevi) are benign skin lesions that everyone has, but on rare occasions a skin cancer called malignant melanoma appears as what looks like a change in a mole. Melanoma is the most malignant of the skin cancers and has a tendency to metastasize early, yet finding and excising the lesion while it is still thin changes the course of what follows enormously. In other words, noticing a change in a mole and seeing a doctor early is, quite literally, an act that protects your life.

In Japan the number of melanoma cases is not as high as in Western countries, but cases where detection comes too late stand out. Japanese melanoma has a high proportion of the acral lentiginous type, which arises on the soles of the feet and on the nails, and because these are areas you do not normally look at, they are easily missed. As with preventing lifestyle diseases, making regular skin self-checks a habit matters just as much as any other measure.

Telling Dangerous Moles Apart With the ABCDE Rule

The simple melanoma screening criteria dermatologists use are known as the ABCDE rule. A (asymmetry) means the shape of the mole is not symmetrical. A normal mole is round or oval and symmetrical, while a melanoma has an irregular shape. B (border) means the outline of the mole is jagged or blurred, or pigment is bleeding out into the surrounding skin.

C (color) means several colors are mixed within a single mole, such as black, brown, red, white, and blue. D (diameter) means the diameter is 6 mm or more, with the eraser on the end of a pencil as a rough guide. E (evolving) means the size, shape, color, or height is changing over a short period. If even one of these five items applies, you should see a dermatologist.

Melanoma of the Sole and Nail, Common in Japan

A distinctive feature of melanoma in Japan is the high proportion arising on the soles of the feet, the palms, and the nails, areas that receive little ultraviolet exposure. Melanoma on the sole looks in its early stages like a large mole or a patch of pigmentation, and because it does not hurt, it tends to be left alone. It is also sometimes mistaken for a shoe rub or a corn.

Melanoma of the nail appears as a black longitudinal line in the nail plate, known as longitudinal melanonychia. A single black line runs from the base of the nail to the tip and widens over time. Take particular care if the line is 3 mm or wider, if the color is uneven, or if the pigment has spread onto the skin around the nail, which is called the Hutchinson sign. Make a monthly self-check of the soles of your feet and your nails part of your routine.

Dermoscopy and Skin Biopsy

At a dermatology clinic, the lesion is examined with a special magnifying instrument called a dermatoscope. Dermoscopy is non-invasive and painless, and it allows detailed assessment of pigment patterns and vascular structures that the naked eye cannot see. The doctor checks for the patterns characteristic of melanoma, such as an irregular pigment network, blue-white structures, and irregular vessels, and distinguishes benign from malignant on that basis.

When dermoscopy raises the suspicion of melanoma, a skin biopsy follows, in which part of the tissue is removed and examined under a microscope. If the biopsy confirms a diagnosis of melanoma, the extent of excision is decided according to the thickness of the tumor, known as the Breslow thickness. For an early melanoma, treatment is completed with a local excision in the outpatient clinic and no hospital admission is needed.

Sun Protection Lowers Melanoma Risk

Ultraviolet radiation, and UV-B in particular, damages the DNA of melanocytes and raises the risk of developing melanoma. Risk is higher in people with a history of sunburn in early childhood. As everyday sun protection, effective measures include reapplying a sunscreen of SPF 30 or higher every two hours, blocking the light physically with a hat and long sleeves, and staying indoors during the strong hours between 10 in the morning and 2 in the afternoon.

Understanding how to use sunscreen correctly and the science behind ultraviolet light ties directly into preventing not only melanoma but also photoaging. Deliberately exposing yourself to intense ultraviolet radiation, as in a tanning salon, is thought to raise melanoma risk, and the WHO classifies ultraviolet tanning devices as carcinogenic. Be thorough about sun protection not only for the sake of a fair complexion but from the standpoint of cancer prevention as well.

How and How Often to Do a Self-Exam

Get into the habit of checking the skin over your whole body once a month. In a well-lit room, use a full-length mirror and a hand mirror so that you also cover the places you cannot easily see yourself, such as your back, your buttocks, and the soles of your feet. Having a partner or family member look at your back works well too. The points to check are the appearance of new moles, changes in existing moles in size, color, and shape, and whether there is any bleeding or itching.

Photographing your moles with a smartphone at regular intervals to record how they change over time is also recommended. If there is a clear change compared with a photo from three months earlier, that is a reasonable trigger for a visit. People with 50 or more moles, people with a family history of melanoma, and people taking immunosuppressive drugs are in the high-risk group, and an annual dermatology check is recommended for them. If something worries you, do not let it sit: consulting a specialist early rather than waiting is important.

Key Points of This Article

• Use the ABCDE rule (asymmetry, irregular border, uneven color, 6 mm or more, evolving) to identify a dangerous mole
• Melanoma of the sole and nail is common in Japan, so a monthly self-check matters
• Dermoscopy is non-invasive and extremely effective for early detection
• Sun protection and regular checkups are the two wheels of melanoma prevention and early detection