Melanoma is less common than other skin cancers. However, it is much more dangerous and causes the majority (75%) of deaths related to skin cancer. Worldwide, doctors diagnose about 160,000 new cases of melanoma yearly. The diagnosis is more frequent in women than in men and is particularly common among Caucasians living in sunny climates, with high rates of incidence in Australia, New Zealand, North America, Latin America, and northern Europe. According to a WHO report, about 48,000 melanoma related deaths occur worldwide per year.
The treatment includes surgical removal of the tumor, adjuvant treatment, chemo- and immunotherapy, or radiation therapy. The chance of a cure is greatest when the tumor is discovered while it is still small and thin, and can be entirely removed surgically.
Early signs of melanoma are changes to the shape or color of existing moles or, in the case of nodular melanoma, the appearance of a new lump anywhere on the skin (such lesions should be referred without delay to a dermatologist). At later stages, the mole may itch, ulcerate or bleed. Early signs of melanoma are summarized by the mnemonic "ABCDE":
Borders (irregular)
Color (variegated), and
Diameter (greater than 6 mm (0.24 in), about the size of a pencil eraser)
Evolving over time
These classifications do not, however, apply to the most dangerous form of melanoma, nodular melanoma, which has its own classifications:
Elevated above the skin surface
Firm to the touch
Metastatic melanoma may cause nonspecific paraneoplastic symptoms, including loss of appetite, nausea, vomiting and fatigue. Metastasis of early melanoma is possible, but relatively rare: less than a fifth of melanomas diagnosed early become metastatic. Brain metastases are particularly common in patients with metastatic melanoma.
All cancers are caused by damage to the DNA inside cells. This damage can be inherited in the form of genetic mutations, but in most cases, it builds up over a person's lifetime and is caused by factors in their environment. DNA damage causes the cell to grow out of control, leading to a tumor. Melanoma is usually caused by damage from UV light from the sun, but UV light from sunbeds can also contribute to the disease.
In July 2009, the IARC released a report that categorized tanning beds as “carcinogenic to humans”. The agency, which is part of the World Health Organization (WHO), previously classified tanning beds as “probably carcinogenic”. The change comes after an analysis of more than 20 epidemiological studies indicating that people who begin using tanning devices before age 30 are 75% more likely to develop melanoma.
In December 2009, Julie Morgan, Labour MP for Cardiff North, introduced a Private Member's Bill before Parliament aimed at preventing under-18s using sunbeds. MPs considered the evidence, including research from a UK cancer charity. The research found that a quarter of a million children in England between the ages of 11 and 17 regularly used sunbeds. The bill was passed in April 2011; the Sunbed (Regulation) Bill restricts the use of sunbeds to over-18s in England and Wales (Scotland already had this legislation). All sunbed salons will have to be staffed and provide accurate health information on the dangers of sunbeds.
ABCD rule illustration: On the left side from top to bottom: melanomas showing (A) Asymmetry, (B) a border that is uneven, ragged, or notched, (C) coloring of different shades of brown, black, or tan and (D) diameter that had changed in size. The normal moles on the right side do not have abnormal characteristics (no asymmetry, even border, even color, no change in diameter).
There is no blood test for detecting melanomas. Visual diagnosis of melanomas is still the most common method employed by health professionals.To detect melanomas (and increase survival rates), it is recommended to learn what they look like (see "ABCDE" mnemonic below), to be aware of moles and check for changes (shape, size, color, itching or bleeding) and to show any suspicious moles to a doctor with an interest and skills in skin malignancy.
A popular method for remembering the signs and symptoms of melanoma is the mnemonic "ABCDE":
Asymmetrical skin lesion.
Border of the lesion is irregular.
Color: melanomas usually have multiple colors.
Diameter: moles greater than 6 mm are more likely to be melanomas than smaller moles.
Enlarging: Enlarging or evolving
A weakness in this system is the diameter. Many melanomas present themselves as lesions smaller than 6 mm in diameter; and all melanomas were malignant on day 1 of growth, which is merely a dot. An astute physician will examine all abnormal moles, including ones less than 6 mm in diameter. Seborrheic keratosis may meet some or all of the ABCD criteria, and can lead to false alarms among laypeople and sometimes even physicians. An experienced doctor can generally distinguish seborrheic keratosis from melanoma upon examination, or with dermatoscopy.
Some will advocate the system "ABCDE", with E for evolution. Certainly moles which change and evolve will be a concern. Alternatively, some will refer to E as elevation. Elevation can help identify a melanoma, but lack of elevation does not mean that the lesion is not a melanoma. Most melanomas are detected in the very early stage, or in-situ stage, before they become elevated. By the time elevation is visible, they may have progressed to the more dangerous invasive stage.
However, nodular melanomas do not fulfill these criteria, having their own mnemonic "EFG":
Elevated: the lesion is raised above the surrounding skin.
Firm: the nodule is solid to the touch.
Growing: the nodule is increasing in size.
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