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Chapters
0:00 Introduction
1:04 Causes of Melanoma
2:13 Symptoms of Melanoma
2:39 Diagnosis of Melanoma
4:00 Treatment of Melanoma
Melanoma, also redundantly known as malignant melanoma,[7][8][9] is a type of skin cancer that develops from the pigment-producing cells known as melanocytes.[1] Melanomas typically occur in the skin but may rarely occur in the mouth, intestines or eye (uveal melanoma).[1][2] In women, they most commonly occur on the legs, while in men they most commonly occur on the back.[2] About 25% of melanomas develop from moles.[2] Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness or skin breakdown.[1]
The primary cause of melanoma is ultraviolet light (UV) exposure in those with low levels of the skin pigment melanin.[2][10] The UV light may be from the sun or other sources, such as tanning devices.[2] Those with many moles, a history of affected family members and poor immune function are at greater risk.[1] A number of rare genetic conditions such as xeroderma pigmentosum also increase the risk.[11] Diagnosis is by biopsy and analysis of any skin lesion that has signs of being potentially cancerous.[1]
Using sunscreen and avoiding UV light may prevent melanoma.[2] Treatment is typically removal by surgery.[1] In those with slightly larger cancers, nearby lymph nodes may be tested for spread (metastasis).[1] Most people are cured if spread has not occurred.[1] For those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy or chemotherapy may improve survival.[1][12] With treatment, the five-year survival rates in the United States are 99% among those with localized disease, 65% when the disease has spread to lymph nodes and 25% among those with distant spread.[4] The likelihood that melanoma will reoccur or spread depends on its thickness, how fast the cells are dividing and whether or not the overlying skin has broken down.[2]
Melanoma is the most dangerous type of skin cancer.[2] Globally, in 2012, it newly occurred in 232,000 people.[2] In 2015, there were 3.1 million people with active disease, which resulted in 59,800 deaths.[5][6] Australia and New Zealand have the highest rates of melanoma in the world.[2] There are also high rates in Northern Europe and North America, while it is less common in Asia, Africa and Latin America.[2] In the United States melanoma occurs about 1.6 times more often in men than women.[13] Melanoma has become more common since the 1960s in areas mostly populated by people of European descent.[2][11]