Cutaneous melanoma, more commonly known simply as melanoma, is a cancer of skin cells called melanocytes. These are pigment-producing cells located mainly in the skin, with small numbers of melanocytes also present in the ears, eyes, gastrointestinal tract and mucous membranes. Cutaneous melanoma is the cause of the majority of deaths from skin cancer, but it can be treated effectively if diagnosed before the cancer has spread from its point of origin. The most effective ways to combat melanoma are the preventative measures of avoiding prolonged sun exposure, sunburn and heavy tanning and of using sunblock and protective clothing when outdoors.
One of the most common warning signs of melanoma is changes in existing skin lesions. The changes that can occur are defined by the ABCDE criteria. The first three criteria are asymmetry, where the two halves of the lesion do not match; border irregularity, where the edges of the lesion are ragged rather than smooth; and color variegation, where pigmentation of the lesion is not the same over its entire surface. The fourth criterion is diameter, which refers to the fact that most cutaneous melanoma lesions are more than about one-fourth of an inch (6 mm) in diameter. The fifth criterion is evolving, which signifies that the appearance of malignant melanoma lesions changes over time.
There are several risk factors for cutaneous melanoma. People with pale skin, fair hair, light-colored eyes or a tendency to freckle after sun exposure have an increased risk of skin cancer. The risk is further increased when there is a family history of melanoma. The role of sun exposure in the development of melanoma is not completely understood, but it is known that heavy sun exposure in childhood is a risk factor, particularly if one or more blistering sunburns are suffered. Heavy use of tanning beds or sunlamps also is thought to increase the risk of melanoma.
The primary treatment for cutaneous melanoma is surgical removal of the malignant skin lesion. Where the skin lesion is superficial in depth, this often can be carried out as an outpatient procedure at a clinic or hospital. As long as the cancer has not spread from the point of origin, surgical removal is enough to cure the disease. If the melanoma lesion is more than .04 inches (1 mm) deep, however, there is the possibility that the cancer might have spread to the nearest lymph node. In such cases, a biopsy is carried out to determine if this has occurred.
Unfortunately, when the cancer has spread from the initial lesion to one or more lymph nodes, additional treatment such as chemotherapy is rarely successful. Metastatic melanoma is fatal for the majority of people, with a five-year survival rate of less than 20 percent. Treatment with immune-boosting cytokines such as interferon alpha and interleukin-2 has proven successful for some patients, but the prognosis remains poor for people with metastatic melanoma.