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Melanoma is a cancer that arises most commonly on the skin. Melanoma begins in the pigmented cells (melanocytes) that give color to our skin, although not all melanomas are pigmented in appearance. Although only 3% of skin cancers are melanoma, the vast majority of deaths due to skin cancer are caused by melanoma. According to the American Cancer Society, it is estimated that nearly 63,000 new cases of melanoma will be diagnosed in the United States this year, and more than 8,000 patients will die of the disease. When diagnosed and treated at its earliest stage, however, melanoma can be cured in 95% of patients. As with many other cancers, though, more advanced stages of melanoma can be very difficult to cure, and this fact emphasizes the importance of screening for melanoma.
Most skin melanomas develop on sun-exposed skin, and in more than half of all cases, in areas where no moles were previously noticed. Fair-skinned individuals are at greatest risk of developing melanoma (and other skin cancers), although dark-skinned individuals can also develop this disease. While Caucasians are at 10 times greater risk of developing melanoma when compared to people with darker skin, Asians and African Americans who develop melanoma tend to present with more advanced disease than their fair-skinned counterparts. The reason for this disparity is most likely due to the fact that melanoma in dark-skinned individuals tends to present differently than in light-skinned individuals. In particular, melanomas are more likely in dark-skinned individuals to occur underneath fingernails and toenails (subungual melanomas), on the nonpigmented areas of the palms and sole, and on mucosal surfaces such as the mouth, nasal cavities, rectum and vagina (melanomas may arise in these same locations in Caucasians as well). Because melanomas may become quite advanced in these areas before a patient even notices their presence, there is a higher risk that the disease will have spread to other parts of the body in such cases. The myth that people of color do not ever have to worry about developing melanoma is both incorrect and potentially deadly. (There is also an even rarer variant of melanoma, ocular melanoma, which occurs within the eye itself.)
If you are fair-skinned and have light-colored or red hair, light-colored eyes, or freckles; if you sunburn easily; if you already have moles on your skin; and/or have a history of blistering sunburns during childhood or early adulthood, you may be at increased risk of developing melanoma. A family history of melanoma (especially if also associated with a family history of pancreatic cancer) also significantly increases your risk of developing this disease.
Although it has not been conclusively proven that the frequent use of sunscreen can prevent melanoma, it is known that UV light exposure (from the sun, or from tanning beds) is associated with an increased risk of developing melanoma. Therefore, the best approach to preventing melanoma is avoidance of excessive exposure to UV rays, particularly if you already have any of the known risk factors for melanoma. Using sunscreen when exposed to the midday sun, when sun exposure cannot be avoided, may also reduce the risk of developing melanoma. Whenever possible, protective clothing should also be worn when high-risk people must be outdoors during mid-day.
High-risk individuals should regularly examine all accessible areas of their skin for new spots or lumps, or for changes in existing moles or other skin lesions. Your physician should also incorporate a careful total body skin exam during all routine physical examinations, including areas that the you cannot easily see yourself. It also may be helpful to have your spouse or another person look over the areas of your body that you cannot easily see yourself. Remember that fewer than one-half of new skin melanomas develop from existing moles. Looking at it another way, more than half of new melanomas will arise in places where there were previously no moles. Therefore, any new moles, or changes in existing moles, should prompt a visit to your physician, and consideration of a referral to a Dermatologist or Surgical Oncologist.
A simple mnemonic, “ABCD” (and some people add “E” as well), has been developed to call attention to the features of high-risk pigmented skin lesions. Although this memory-jogger is helpful, another myth is that all melanomas are darkly pigmented, or that they are all large or irregular tumors. Not only are these myths untrue, but a particularly deadly type of melanoma, nodular melanoma, is often the same color as the surrounding normal skin, and may be quite small, and have regular, smooth borders.
Although any skin lesion that is new, or has recently changed, should be considered for biopsy even if it does not follow any of the following “rules,” the “ABCD” rule is still very helpful when evaluating moles or other pigmented skin lesions for melanoma:
Asymmetry – one half of the mole does not match the other half.
Border irregularity – the edges of the mole are ragged or notched.
Color – the color of the mole is not the same all over. There may be shades of tan, brown, or black, and sometimes with patches of red, blue, or white coloration.
Diameter – the mole is wider than about 1/4 inch (although smaller lesions may still be melanoma).
Other important signs of melanoma include changes in the size, shape, or color of a mole. An additional “E” rule is sometimes also added to the “ABCD” rule, where the “E” stands for “elevation.” This applies to lesions on the skin that are not flat, but which have all or part of their surface elevated above that of the surrounding normal skin.
It must be stressed, once again, that not all melanomas will have any or all of the features listed in the “ABCD” rule, and so any new or changing skin lesions should be evaluated by a qualified physician for possible biopsy. Early diagnosis and treatment of melanoma will result in a cure in most cases. Unfortunately, once melanoma has spread to other organs in the body, it can be extremely difficult to control.
Finally, other warning signs that a pigmented area on the skin might be melanoma include: itching, an increase in size, or the development of “satellites” of pigmented spots around a larger, central pigmented lesion (ulceration or bleeding within a pigmented lesion are often signs of more advanced melanoma). Although there are always exceptions to the rule, melanoma in women occurs more commonly on the arms and legs, while the trunk or head and neck are more common sites in men; but it must be reiterated that melanoma can arise on any portion of the skin.
A biopsy, preferably involving complete excision of the skin lesion, should be performed for any suspicious lesions, and the biopsy specimens should be examined by an experienced pathologist to allow for accurate staging (because the prognosis, or likelihood of cure, is related to how deeply the melanoma penetrates into the skin, lesions suspicious for being melanoma should never be “shaved off” or frozen or burned).
Although multiple factors are known to be important in the prognosis of patients with melanoma, the most important prognostic factors for melanoma are: (1) tumor thickness, (2) the presence or absence of melanoma tumor cells within the lymph nodes, and (3) and the presence or absence of melanoma in other organs outside of the skin and lymph nodes. For these reasons, it is critically important that melanoma be treated by a surgeon with special training and experience in evaluating and treating melanoma, including the complete surgical removal of melanoma tumors and the performance of a highly specialized type of lymph node biopsy (sentinel lymph node biopsy). Surgical Oncologists receive extensive additional training in these techniques, as well as in the biology of melanoma and other cancers, and in the comprehensive, multidisciplinary management of such cancers.
Surgery remains the primary treatment for melanoma, although radiation therapy and chemotherapy or immunotherapy may also be utilized in highly selected cases. Your Oncologist may also recommend that you consider participation in a clinical research trial designed to try and identify effective new treatments for melanoma. Remember: when diagnosed at an early stage, most melanomas are curable with surgery alone. If you have any concerns regarding a new (or changing) lesion on your skin, you should seek evaluation by your physician.
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