Melanoma is a cancer of the skin or mucous membranes, developed at the expense of melanocytes.
Its seat is the original skin in the vast majority of cases. There are, however, melanoma of the eye (choroidal melanoma), mucous membranes (mouth, anal canal, vagina), and even more rarely in internal organs.
Melanoma can be formed on a mole pre-existing type nevus or de novo on previously free skin (in this nearly three-quarters of cases). The presence of solar keratosis encourages the development of this cancer.
It first appears as a single pigmented stain.
The burning sun, especially in childhood, and family history are the major risk factors. Sun exposure and moderate to regular skin tan may have a protective effect. Although it may appear anywhere, melanoma tends to form more often on body parts that are covered in daily life but occasionally exposed during sunbathing, as the torso and legs. Similarly, the use of artificial ultraviolet purposes tanning increases the risk of melanoma with a clear correlation with the doses taken.
It also suggests a moderate increase in the risk of developing melanoma if a history of endometriosis or fibroids of the uterus in women.
The color also plays an important role: the risk is more than doubled in the red and markedly increased in people with pale skin. It is more than ten times lower for people of color of skin not white.
5 to 10% of patients with melanoma have a family history of the disease. A mutation in the CDKN2A gene located on chromosome 9 is associated with cancer.
Its impact increases over 2% per year, but it tends to stabliliser in some countries, probably because of changes habituded'exposition sun. However, its mortality is steadily decreasing, probably because most melanomas detected are small, and therefore better prognosis.
The prognosis is determined by the thickness of the primary tumor (Breslow index) is measured in millimeters from the point the superficial to the deepest point of the tumor, supplemented by the Clark index ranging from 1 to 5 next layer of the skin the deeper reaches of the tumor, and the result of staging (search for metastases). At the initial stage of superficial spreading, the prognosis is nearly 100% survival at 10 years.
Only the total excision of the lesion will cure melanoma. The safety margins, that is to say the surface of healthy skin to be removed with melanoma depends on its thickness. Until the 1980s, the current margin of excision was about 4 to 5 cm around the lesion, causing significant scarring or disfigurement. The safety margin is currently favored few millimeters.
The staging is based primarily on local thickness (Breslow index) and the presence of micro-ulcerations. The sentinel node biopsy (rather than draining the melanoma) is also a standard procedure in the evaluation of its extension.
Various protocols of chemotherapy or immunotherapy may be offered for advanced stages, including treatment with interferon, the latter giving mixed results.
It depends on the sunscreen (especially children) and consulting a dermatologist for a variation of a mole or appearance of a black skin lesion.
It is recommended especially wary of lesions that are (rule "ABCDE"):
* A: Asymmetric,
* B: irregular edges,
* C: Coloring inhomogeneous (the spot is several colors)
* D: diameter large (> 6 mm)
* E: Scalable, whose appearance changes with time.
These rules are even more important that we have a family history of melanoma.
Experimentally, vitamin C combined with copper would have a toxic effect on melanoma cells that accumulate copper ions.
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