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Melanoma Explained

Melanoma explained

What is melanoma?

Malig­nant melanoma is the most seri­ous type of skin can­cer. Over the last decade, global annual rates of melanoma have risen by almost 50% to more than 287,000 cases.

Melanoma starts in the melanocytes. These cells are found in the out­er lay­er of the skin (at the base of the epidermis). Their job is to make melanin — the pig­ment that gives your skin its nat­ur­al colour. Ultraviolet (UV) exposure causes the melanocytes to produce melanin. This results in darker or ‘tanned’ skin.

Over-exposure to UV radiation, typically from the sun, damages the DNA in the melanocytes. This causes the melanocytes to multiply uncontrollably, leading to melanoma. What makes melanoma most dangerous is its ability to quickly spread to other organs. While melanoma makes up a small proportion of skin cancer diagnoses (around 3%), it accounts for 65% of all deaths from skin cancer.

FACT: Just 20-30% of melanomas are found in existing moles. Most (70-80%) appear as a new growth.

Types of melanoma

The four (there are a few other types of melanoma, but these are very rare) main types of melanoma are:

  • Superficial spreading melanoma
  • Nodular melanoma
  • Lentigo maligna melanoma
  • Acral lentiginous melanoma

Let’s take a look at how common these ‘cutaneous’ (that’s Latin and means ‘of the skin’) melanoma types are. Plus, find out which parts of the body they tend to grow on.

Superficial spreading melanoma

Superficial spreading melanoma accounts for around 60-70% of all melanomas, making it the most common. It can develop from an existing mole or appear as a new spot on the skin. It may appear anywhere on the body. Although, it’s commonly found on the torso in men, the legs in women and the upper back in both sexes.

FACT: Superficial spreading melanoma usually grows slowly on the surface of the skin. It becomes dangerous when it grows more deeply.

Nodular melanoma

Nodular melanoma accounts for around 10-15% of all melanoma cases. It’s most often found in people over the age of 65. It tends to be found on areas of the body prone to sun damage. This includes the arms, legs, back of neck, torso, and scalp (particularly in older men).

FACT: Nodular melanoma is fast growing and can quickly spread to the lower layer of the skin (the dermis).

Lentigo maligna melanoma

Lentigo maligna is an early form of melanoma. It grows close to the surface of the skin (the epidermis). However, if left untreated, it can grow deeper into the skin and become a more invasive form of melanoma called lentigo maligna melanoma. 

This type of melanoma makes up around 10-15% of melanoma diagnoses. It most often occurs on the face, ears, neck, and head in older people with sun-damaged skin. Lentigo maligna melanoma can be easily missed, as it grows slowly and may look like a non-cancerous freckle.

FACT: Lentigo maligna is also known as Hutchinson melanotic freckle.

Acral lentiginous melanoma

Acral lentiginous melanoma is relatively rare, accounting for less than 3% of all melanomas. It is more common in people with dark skin. It may appear in hard-to-spot areas such as on the soles of feet, under the fingernails or toenails, and on the palms of the hands. It grows slowly but if left untreated, can invade the deeper layer of the skin (the dermis).  

FACT: Acral lentiginous melanoma can look like a lightly-coloured patch of skin and may be mistaken for a stain or bruise.

Want to know more on this topic? Check out these articles

The four (there are a few other types of melanoma, but these are very rare) main types of melanoma are:

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What are the risk factors for melanoma?

Over-exposure to UV radiation is the major risk factor for melanoma and other types of skin cancer. Excessive sun exposure during adulthood and childhood has been found to increase an individual’s melanoma risk. Other risk factors include:

  • Having numerous moles
  • A family/personal history of melanoma
  • Increasing age
  • Fair skin that burns easily
  • Light/red hair and blue or green eyes

Take our quick risk assessment to find out your personal skin cancer risk.

Melanoma warning signs

Melanoma can occur anywhere on the body. Often it grows in places you might not expect, such as areas rarely exposed to the sun. It can develop in an existing mole or freckle. More commonly though, melanoma appears as a new spot. 

The different types of melanoma can appear in various shapes, sizes, and colours. This can make it difficult to detect. Knowing the ABCDE-EFG rules of melanoma can help you to spot the warning signs.

  • A — asymmetrical
  • B — borders are uneven
  • C — colour change
  • D — diameter is large
  • E — evolving in size
  • E — elevated
  • F — firm
  • G — growing

Essentially, if you notice a new or changing mole, or a mole becomes sore or looks abnormal, have it checked out by scheduling a mole check.

What does melanoma look like?

Superficial spreading melanoma is the most common form of melanoma. It may look like a flat or partly raised patch of skin. It tends to be asymmetrical with uneven borders. It can be different colours, from various shades of black through to brown. It may even be pinky-red, white, or bluish in colour. The truth is, melanoma can look different from person to person.

For a better understanding of the signs, it can be useful to look at pictures of skin cancer. Take a look at this gallery of melanoma pictures from the Skin Cancer Foundation, as a helpful guide.

How is melanoma diagnosed?

One Australian is diagnosed with melanoma every 30 minutes. On a positive note—if found early, more than 90% of melanomas can be successfully treated through surgery. Most melanomas are diagnosed with a skin examination (i.e., a skin check). If your medical practitioner suspects melanoma, they will do a biopsy. This is where a small tissue sample is taken and reviewed under a microscope.

Skin examination

This involves a thorough skin examination to spot atypical and potentially cancerous moles or lesions.

Excision biopsy

If a lesion or mole is believed to be melanoma, it pays to remove the entire abnormal area for testing. The most common procedure for this is called an excisional biopsy. The entire mole and a small margin of healthy tissue around it are removed. It’s a straightforward process that can be done by a GP, dermatologist, or a surgeon under local anaesthetic.

Melanoma treatment

Melanoma treatment depends on the stage of the cancer. This is determined by the thickness (vertical depth) of the tumour. Treatment options for melanoma include:

  • Surgery — removal of the melanoma and surrounding tissue
  • Radiation therapy — uses x-rays to destroy the cancer cells and stop them from multiplying
  • Immunotherapy — medications that support the body’s immune system to attack the cancer
  • Targeted therapy — medication to fight the cell mutations that cause the cancer to grow and spread

Melanoma is most effectively treated when it is in its early stages. There are several factors that may affect treatment outcome. This includes the type and stage of cancer, the individual’s age, and health status at the time of diagnosis.

Preventing melanoma

According to the Melanoma Institute Australia, 95% of melanomas are caused by over-exposure to UV light. Protecting your skin against the sun’s UV rays is the single biggest thing you can do to reduce your melanoma risk. 

Practice sun safety

It’s important to wear SPF 50+ sunscreen with broad spectrum UVA and UVB protection. Avoid the sun during the hottest part of the day. Wear protective clothing. And don’t forget to pop on a hat and sunglasses to keep your head and eyes safe. 

Get a skin check

Both melanoma and non-melanoma skin cancers can be effectively treated when diagnosed early. The best way to do this is with regular professional skin examinations, as well as at-home skin checks. Don’t forget, melanoma doesn’t always appear in the most obvious spots. Find out more about the places you might forget to check for skin cancer.

Skin checks

Regular (annually or as directed by your GP or skin specialist) skin checks are an essential element of skin cancer prevention and early detection. Getting to know your skin is the best way to spot new or changed moles.

Dr Franz Strydom
Board member and Censor Skin Cancer College of Australasia
MB ChB. BSc. Hons BSc (Med Sci) MSc. (Med Sci) FRNZCGP FSCCA

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