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What is melanoma

Melanoma is the most serious type of skin cancer

Melanoma occurs when melanocytes (the pigment producing cells in our skin) mutate and become cancerous.

Melanoma can develop anywhere melanocytes are found, however are most likely to be found on the skin.  Melanoma can also develop in areas of the body that may not receive a lot of sun exposure, such as the soles of your feet, or in between your toes. It can also develop in the eyes (ocular melanoma), in the nail bed (acral lentiginous melanoma), and on internal mucosal surfaces (mucosal melanoma). Mucosal surfaces include the lining of the sinuses, mouth, anus, or vagina.

How common is melanoma?

In Australia, melanoma is the third most common cancer among both men and women. It makes up 2% of all skin cancers but is responsible for 75% of skin cancer deaths because it is more likely to metastasise (spread), to other parts of the body. When it spreads to other organs it is harder to treat.

According to the Australian Institute of Health and Welfare, in 2020, an estimated 16,221 cases of melanoma were diagnosed in Australia, approximately 65% in men and 35% in women. It is estimated that 1,375 people died from Melanoma in 2020.1 

What causes melanoma?

All cancer occurs because of gene mutations. Our genes are like the blueprint that our body uses as a set of instructions. If there is a mutation (a serious change to one of these instructions) it can result in a cell multiplying uncontrollably and becoming cancerous.

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Episode 1: The Fundamentals and Treatment of Early Stage Melanoma

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What causes the mutations?

Cancer-causing mutations can fall into two categories: Acquired gene mutations and familial (inherited) mutations

Acquired gene mutations

Acquired gene mutations are the most common cause of cancer. These gene changes have developed from damage to genes during a person’s life and cannot be passed from parent to child.

When our melanocytes in our body are performing correctly, they produce pigment in our skin which in turn protects our skin from damaging ultraviolet (UV) radiation. When there is too much UV radiation for the melanocytes to absorb, it will cause damage to the DNA. The most common cause of excessive UV radiation is overexposure to the sun or artificial sunbeds and solariums. Melanoma can then develop when melanocytes mutate and multiply in an uncontrolled way.

Familial genes

Familial genes are a less common cause of melanoma than acquired mutations from UV radiation. This mutation passes directly from parent to child and can increase their risk of melanoma. There are also characteristics that you can inherit from a parent that may increase your susceptibility for developing melanoma. For example, our different skin colours, how quickly we burn in the sun and how many moles we develop.

What are the risk factors for melanoma?

A risk factor is anything that can increase your risk of developing certain cancers. These can be related to your behaviours, lifestyle or family history.

The leading cause of melanoma is exposure to ultraviolet (UV) radiation. The risk of developing melanoma grows with the amount of UV exposure, especially each time you experience sunburn. It can be years and even decades before any signs of melanoma begins so it is important for all ages and all skin types to reduce UV exposure.

Moles or melanoma?

aised from the skin’s surface. They usually develop in childhood and the number of moles a person has is influenced by genetics as well as sun exposure. The medical term is “nevus” and they can form anywhere on your skin’s surface. Moles are generally classified into these categories:

  • Congenital Moles are moles that are present at birth, and if larger than 20mm, can have an increased risk of turning into skin cancer
  • Acquired Moles are those that develop after birth and will usually not develop into skin cancer. However, people with 50 or more normal moles have a higher risk of developing melanoma. Any moles that become itchy or start to bleed should also be checked by your GP or skin specialist.
  • Atypical Moles (also called dysplastic nevi) are normally larger than a pencil eraser and uneven in colour and shape. They can have asymmetrical, irregular borders and often the colour is uneven where darker spots can appear within the mole. The more atypical moles that you have, the higher your risk of skin cancer.

Overall, moles that are more likely to develop into cancer are ones that may grow or change shape, size or colour. If you notice any change in the appearance of a mole, or if you develop a new mole as an adult, you should see your GP or skin specialist.

Early detection is important because when melanoma is found and treated early, the chances for long-term survival are excellent. As melanoma progresses, it becomes increasingly harder to treat, and is likely to have a worse outcome. Examine your skin every month to look out for any new or changing moles and use the ABCDE rule to recognise anything suspicious that you want your skin specialist to investigate further.

Skin tone

Melanoma can develop in any skin tone, but it does occur more frequently in people with fair or freckled skin. If you have skin that burns and does not tan easily, or you have a tendency to develop freckles after sun exposure, you are at a greater risk of developing melanoma. People with blue or green coloured eyes, as well as those with blonde or red hair are also at higher risk.

UV exposure

Ultraviolet (UV) radiation is part of the natural energy produced by the sun, and by artificial sources, such as tanning beds. UV exposure over your lifetime and episodes of severe sunburns increase the risk of developing melanoma and other skin cancers such as basal cell carcinoma and squamous cell carcinoma.

The sun’s UV rays are present even when it’s a cloudy day and the sun doesn’t appear to be shining. UV can be reflected by surfaces like water, snow, pavement and sand. The amount of radiation increases in warmer seasons, reaching its highest levels during summer. In Australia, our northern regions like QLD and the Northern Territory will have higher UV levels than our southern regions like Tasmania.

Latitude: The closer to the equator, the higher the UV radiation levels.

Altitude: The higher the altitude, the higher the UV radiation levels.

What are the types of UV rays?

There are three types of UV radiation from the sun: UVA, UVB, and UVC. All can cause skin and eye damage.

UVA

UVA is the most common type of UV to reach our skin. It is not absorbed at all by the ozone layer and even penetrates through clouds and car windows all throughout the year.

UVA rays have a longer wavelength that can penetrate through to the middle layer of your skin (dermis) and causes wrinkling and premature aging (remember “A” for “Aging”) as well as increasing your risk for developing skin cancer

UVB

UVB radiation is absorbed somewhat by the Earth’s ozone layer but will still reach unprotected skin and penetrate the top layer (epidermis) and cause damage to the skin’s DNA. Because UVB has higher energy levels than UVA it is responsible for causing sunburn (remember “B” for burns) and is strongly linked to skin cancer. Exposure to UVB does help the skin to produce Vitamin D, which along with calcium pays an important role in bone and muscle health. It might be useful to speak to your GP about your Vitamin D levels.

UVC

UVC is the most dangerous type of UV radiation, but luckily it never reaches Earth because the ozone absorbs it.

Because of this, it is not usually considered a risk for skin cancer, however, there are other sources of UVC, such as in arc welding and the use of certain lasers, from which workers need to protect themselves with face-shields, protective clothing, and eye protection.

The UV index

The UV Index is a tool created to help you make informed decisions about how much time you should spend in the sun, and what types of protection you should use. The index predicts the amount of skin-damaging UV rays on a scale of 0 (minimal risk) to 11+ (very high risk). Sun protection is required when the UV index is three or above.

Check Your Local UV Index

The Cancer Council SunSmart app / website is great for checking if the UV index is three or above.

Sun exposure

Cumulative sun exposure and the number of episodes of sunburn will increase your risk for melanoma and other skin cancers. The sun’s UV rays also damage the fibres in the skin called elastin. When these fibres break down, the skin loses its elasticity and becomes leathery and wrinkly. Tanning is DNA damage. While you may like the look of tanned skin, it’s important to understand that the darkening of your skin is objective evidence of DNA damage.

Indoor tanning

Due to the associated health risks, commercial solariums were banned in all states and territories in Australia in 2016. Before that ban it was estimated that each year in Australia, solarium use led to: 281 new melanoma cases; 43 melanoma-related deaths, and; 2,572 new cases of squamous cell carcinoma.2

Family and Personal History

The risk of developing melanoma can be over twice as high in people with a first-degree relative (such as a parent, brother or sister) who has melanoma; therefore, it is important to know whether anyone in your family has been diagnosed. The increased risk might be because of certain gene changes (mutations), a shared family lifestyle of frequent sun exposure, families with lighter skin tone, or a combination of these factors. People who have previously been diagnosed with skin cancer are also at increased risk of developing the disease again.

A weakened immune system, due to other diseases or certain drug treatments and older age are also risk factors.

Of all the above risk factors for melanoma, only lifetime sun exposure, sunburn, and artificial UV light exposure, such as from tanning beds, are within a person’s control. Avoiding overexposure to the sun and other UV light and preventing sunburn can significantly lower the risk of developing melanoma

Age and risk

Melanoma can affect people of all ages, from the young to the elderly, and everyone in between. Melanoma is often considered a disease of older people, since in Australia the average age for melanoma diagnosis is 63 for men and 60 for women.3 While older adults are at higher risk of developing melanoma, the incidence of melanoma is rapidly rising in young adults. In fact, melanoma is now the most common cancer affecting 15 to 39 year olds in Australia. So yes, age is a risk factor for melanoma, but the risk of developing the disease is not limited to older adults.

Melanoma annual incidence in Australia in 2014 reflected that melanoma frequency increases with age, as follows:

  • Age 0 – 24: 1.9 per 100,000
  • Age 25 – 49: 30.1 per 100,000
  • Age 50 -74: 113.7 cases per 100,000
  • Age over 75: 236 cases per 100,0004

Young people are at greater risk if there is a family history of melanoma; therefore, even young children should be screened in this circumstance.

From 2007 to 2018 in Australia, the incidence rate increased in females from 4,409 cases to 6,330 cases. And for men the incidence rate rose from 10,450 cases to 15,229 cases in 2018.5

The “Ugly Duckling”

Most moles and spots on your body will look pretty similar to each other. An “Ugly Duckling” is a mole or lesion that is unlike the others on your skin. It might be a lighter coloured or darker coloured mole or spot than the others around it, or it might be a larger or smaller mole or lesions than others around it. If you have an Ugly Duckling, show it to your healthcare provider and keep your eyes out for other different looking moles and lesions.

Self Skin check

Self skin check
The “Ugly Duckling”

Know your ABCDE’s

Examine your skin regularly, looking for any new moles or lesions as well as changes in the moles you already have. When you examine your moles, remember the ABCDEs of melanoma, and the “Ugly Ducking” Rule. If you notice any of the following, consult your healthcare provider immediately.

A = Asymmetry: Is the spot asymmetric?

B = Border: Are the borders uneven?

C = Colour: Does the spot contain different colours?

D = Diameter: Is the spot larger than 5m in diameter?

E = Evolving (or changing): Have you noted an evolution or growth of the spot?

  1. Melanoma of the Skin Statistics, accessed 29/03/2021 ↩︎
  2. Gordon, L. Hirst, N.Gies, P.Green, C. 2008. What impact would effective solarium regulation have in Australia. Medicine and the Media. MJA 2008; 189: 137-378 ↩︎
  3. Cancer Council Australia. Skin cancer incidence and mortality. Skin Cancer Statistics and Issues accessed 24/05/2021 ↩︎
  4. accessed 29/03/2021 ↩︎
  5. accessed 29/03/2021 ↩︎