Moles & Melanoma
It is one of the rarer types of skin cancer but causes the majority of skin cancer related deaths. Malignant melanoma is a serious type of skin cancer. It is due to uncontrolled growth of pigment cells, called melanocytes. Around 160,000 new cases of melanoma are diagnosed worldwide each year, and it is more frequent in males and caucasians. It is more common in caucasian populations living in sunny climates than other groups.
Generally, an individual's risk for developing melanoma depends on two groups of factors: intrinsic and environmental. "Intrinsic" factors are generally an individual's family history and inherited genotype, while the most relevant environmental factor is sun exposure. Epidemiologic studies suggest that exposure to ultraviolet radiation (UVA and UVB) is one of the major contributors to the development of melanoma. UV radiation causes damage to the DNA of cells, typically thymine dimerization, which when unrepaired can create mutations in the cell's genes.
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.
- Evolving: any change -in size, shape, color, elevation, or any new symptom such as bleeding, itching or crusting - points to danger.
|Borders are even||Borders are uneven|
|One shade||Two or more shades|
|Smaller than 1/4 inch||Larger than 1/4|
Skin Cancer Foundation (www.skincancer.org)
Minimizing exposure to sources of ultraviolet radiation (the sun and sunbeds), following sun protection measures and wearing sun protective clothing(long-sleeved shirts, long trousers, and broad-brimmed hats) can offer protection. In the past it was recommended to use sunscreens with an SPF rating of 30 or higher on exposed areas as older sunscreen more effectively blocked UVA with higher SPF. Currently, newer sunscreen ingredients (avobenzone, zinc, and titanium) effectively block both UVA and UVB even at lower SPFs.
Moles that are irregular in color or shape are suspicious of a malignant or a premalignant melanoma. Following a visual examination and a dermatoscopic exam used routinely by one in 4 dermatologists in the United States, or an examination using other in vivo diagnostic tools, such as a confocal microscope, the doctor may biopsy the suspicious mole. If it is malignant, the mole and an area around it needs excision.
The diagnosis of melanoma requires experience, as early stages may look identical to harmless moles or not have any color at all. A skin biopsy performed under local anesthesia is often required to assist in making or confirming the diagnosis and in defining the severity of the melanoma. Amelanotic melanomas and melanomas arising in fair skinned individuals are very difficult to detect as they fail to show many of the characteristics in the ABCDE rule. These melanomas are often light brown, or pink in color - and very hard to distinguish from acne scarring, insect bites, dermatofibromas, or lentigines. There is no blood test for detecting melanomas.