The skin and melanoma
The skin is the largest organ of our integumentary system. It serves as protection, regulation and sensation. The skin made up of cells such as melanocytes that produce a brown-black pigment called melanin which gives the skin its colour.
When one exposed to the sun, melanocytes produce extra melanin as part of skin protection from getting sunburn. This is what causes people to tan after sun exposure. Melanocytes can also be found in benign spots on the skin (moles). Most moles are brown, tan or pink in colour and round in shape. Most moles are quite safe and harmless, however, we need to conduct skin checks regularly as they have the potential of turning into skin cancer.
What is melanoma?
Melanoma is one of the most serious forms of skin cancer that develops in melanocytes (skin’s pigment cells). It usually occurs on body parts that have been overexposed to the sun. However, in rare cases, melanoma can evolve in the area where has never been exposed to the sun, such as the nervous system, eye and mucous membrane. Melanoma develops when DNA damage (most often caused by ultraviolet radiation from sun exposure or tanning beds) to the skin cells leads the melanocyte to multiply rapidly in an uncontrolled and unregulated way and form malignant tumors.
Although melanoma is one of the least common skin cancers, it is one of the most threatening as it is more likely to spread to other parts of the body, especially if not detected and treated early. According to the Australian Institute of Health and Welfare reports, Australia and New Zealand have the highest rates of melanoma in the world and it is the 4th most commonly diagnosed cancer in Australia.
One in 18 Australians diagnosed with melanoma before the age of 85. The incidence rate is higher among men than women. The report shows the number of melanomas diagnosed in Australia increased from 3,526 on 1982 to an estimated 13,280 in 2016.
Types of melanoma
Cutaneous melanomas are categorised by their appearance, thickness and how far they have spread.
This is the earliest stage of a skin cancer. ‘In situ’ means that the cancer cells have not had the opportunity to spread to anywhere else in the body. They are only in the epidermis with no penetration into the dermis.
Superficial spreading melanoma
Based on Skin Cancer Foundation research, this type of melanoma is the most common type, accounting for about 70 percent of all cases. It is more often seen in young people and grows along the top layer of the skin for a fairly long time before penetrating more deeply. It starts as a brown or black spot that spreads across the epidermis and becomes dangerous when it invades the dermis.
Lentigo maligna melanoma (LMM)
It is similar to the superficial spreading type but more common in older people. It begins as a large freckle (lentigo) in an area of skin that has had a lot of sun exposure, such as the face, ears, neck and head. LMM may grow slowly and superficially over many years until it penetrates more deeply into the skin.
Acral lentiginous melanoma
It is a rare but distinctive subtype of melanoma. It’s quite different from other types as it appears as a black or brown discoloration under the nails, on the palms of hands or on the soles of feet. This type of melanoma spreads superficially first before penetrating deeply and can progress more quickly than other types of melanoma. According to the Skin cancer foundation, it commonly found in dark-skinned people such as African-Americans and Asians over the age of 40.
This is the most aggressive type of melanomas. It appears as a raised lump (red, pink, brown or black in colour) on the surface of the skin that feels firm to touch. It mostly develops on the trunk, legs, and arms, mainly of elderly people, as well as the scalp in men.
This type of melanoma is rare and presents as a firm scar-like nodule with a smooth or irregular surface. Desmoplastic melanoma occurs more often on the head or neck and mostly are skin-coloured and not pigmented.
Who is at risk?
Anyone can develop melanoma. However, the following factors may increase a person’s risk:
As with all skin cancers, people with fairer skin who often have lighter hair and eye colour as well are at increased risk. These skin types are known as Fitzpatrick I or II, their skin burns easily and does not tan.
Having lots of moles
Atypical moles can be precursors to melanoma, and having them puts you at increased risk of melanoma. But regardless of type, the more moles you have, the greater your risk for melanoma will be. Adults with more than 10 moles on their arms and more than 100 on their body have an increased risk.
Childhood tanning or sunburn
Too much sun exposure during childhood and adolescence greatly increases the chance of getting melanoma in later life because damaged cells have more time to develop into cancer.
Melanoma is related to the pattern of UV exposure and not just the amount. Sunburns in childhood or later in your life and cumulative exposure are the main factors. People who live in locations that have more sunlight such as Australia, New Zealand, Florida and Hawaii, develop more skin cancers. People with occasional high UV exposure and sunburns, such as on weekends and holidays, are also at increased risk of melanoma.
Melanoma is more common in people over 50 years of age as their immune system is weakened. A person’s immune system helps fight cancers of the skin and other organs. People with weakened immune systems from certain diseases or medical treatments are more likely to develop any types of skin cancer, including melanoma.
People with a previous history of skin cancer (BCC or SCC) are at increased risk. Also, people with a strong family history of melanoma have a 50 percent greater chance than people who do not have a family history of skin cancer.
ABCDEs signs of melanoma
Usualy moles and brown spots on our skin are harmless however it’s so important to recognise any changes in the moles on your body. Look for the ABCDE signs of melanoma, and if you see one or more signs, make an appointment with a physician immediately.
benign moles are always symmetrical. If you draw a line through the middle, the two sides will match. Asymmetrical mole may be a warning sign for melanoma.
A benign mole has smooth, even borders, unlike melanomas. The borders of an early melanoma tend to be uneven and the edges may be scalloped or notched.
Most benign moles are all one colour. When the lesion become blotchy with varying colours or with a number of different shades of brown, tan or black it may be the sign of melanoma. A melanoma may also become red, white or blue.
Benign moles usually have a smaller diameter than malignant ones. Melanomas are usually larger than 6mm in size.
Common, benign moles look the same over time. Be on the alert and see a doctor if you notice any changes in size, shape, colour and elevation of your mole or if you experience any new symptom such as bleeding, itching or crusting.
How to prevent melanoma?
Research on melanoma shows that people who have had a lot of sunburns especially during the first 20 years of their life are at particular risk of Melanoma. The use of artificial sources of ultraviolet light such as sunbeds also raises the risk of getting a melanoma, even if the skin tans without burning.
Melanoma Institute Australia has released a list of things to do to prevent Melanoma:
In summary, make sure to practice all sun safety carefully throughout the year and examine your skin head to toe once a month, looking for any suspicious lesions. Self-exams help you identify potential skin cancers at the early stage when they can almost be completely cured. Become familiar with your skin and if you notice any changes to a mole or patch of your skin seek a consultant dermatologist who is expert in diagnosing skin cancer.
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