Melanoma is the most serious type of skin cancer due to its potential to metastasize to other body organs. People can die from melanoma but melanoma can also be cured by surgery alone if caught early. The incidence of melanoma in the United States has been increasing. Melanoma results from changes within the pigment-producing cells called melanocytes. It can occur on its own or within a pre-existing mole. Melanoma can develop on any part of the skin even those areas not commonly exposed to the sun. It can also develop within the eye.
The risk of developing melanoma increases with age but it is also the most common cancer in women aged 25 to 29. It is rare before puberty. There are different types of melanoma: superficial spreading, nodular, lentigo maligna, and acral lentiginous. Up to 70% of melanomas fall into the category of superficial spreading melanoma. It is commonly found on the backs of men and on the legs of women. It appears as a flat to slightly raised irregularly shaped and colored spot.
It is slow-growing often over a period of years. Nodular melanomas are the next most common. They represent 15% to 30% of melanomas and involve deeper layers of the skin. They are rapidly growing over a period of months and occur as a brown, black, blue, or non-pigmented raised lesion. Lentigo maligna melanoma represents 4% to 10% of melanomas. Lentigo maligna occurs on sun-exposed areas, particularly the face, of older individuals.
It is characterized by an irregularly shaped and irregularly colored flat spot. The least common type of melanoma is the acral lentiginous variety, which represents 2% to 8% of melanomas. This type occurs on the palms and soles and is most commonly seen in black individuals. Acral melanomas can also occur on the bed of the fingernail or toenail and are characterized by a dark streak within the nail.
Melanomas are diagnosed with a skin biopsy. Melanomas are staged based on the size of the tumor, whether or not lymph nodes are involved and whether or not the cancer has metastasized. The thickness of the lesion and whether or not ulceration is present are also important factors in determining the severity of the melanoma and prognosis. During skin exams, a trained professional will employ the ABCDs of melanoma when evaluating a lesion.
These include "A" for asymmetry, "B" for borders (looking for jagged or irregular borders), and "C" for color (looking for a mixture of brown, black, red, or a lesion that looks significantly different in color than a patient's other moles) and "D" for diameter (anything 6 mm or larger will draw attention but may not indicate concern if none of the other features are present). If a lesion has any suspicious features a biopsy should be performed. After microscopic evaluation by a pathologist, the diagnosis can be made.
Melanoma is treated through surgery. The entire lesion needs to be excised with a margin of normal tissue to ensure definitive removal. The width of the safety margin needed is determined by the depth of the melanoma. For thicker melanomas, a sentinel lymph node biopsy (SLNB) may be done to check to see if cancer has spread to the lymphatic system.
It is recommended that an individual who has been diagnosed with melanoma have a complete skin exam every 3 months for the first 1-3 years. After this period skin exams should be performed every 6 months. During these exams, the entire skin surface should be evaluated because melanomas can occur in non-sun-exposed areas. The exam will look for evidence of recurrent or metastatic lesions as well as precursor lesions. All immediate family members should also have an annual complete skin examination.
Patients who have received a diagnosis of melanoma can receive support through organizations such as the American Melanoma Foundation (www.melanomafoundation.org). They should also check their skin periodically for new or changing lesions and comply with recommendations for a professional skin check.
Prevention of melanoma and skin cancers, in general, can be facilitated by strict sun protection through the daily appropriate use of sunscreen and sun-protective clothing. Regular skin checks by a trained professional will also help identify skin cancers and potential precursor lesions.