Skin cancer is a type of cancer that starts in the cells of the skin. It’s one of the most common types of cancer – two out of three Australians will be treated for it in their lifetime.

The primary cause of skin cancer is exposure to ultraviolet (UV) radiation from the sun.

Too much UV radiation exposure causes damage to your skin cells’ DNA which your body cannot fix. This damage can cause a skin cancer to grow. There are three main types of skin cancer caused by damage to skin cells from UV radiation:

• Melanoma.
• Basal Cell Carcinoma (BCC)
• Squamous Cell Carcinoma (SCC)

Protecting your skin from UV rays is the best way to prevent melanoma and other skin cancers.

When detecting skin cancer, it’s important to pay attention to any changes in your skin. The more you know your skin the more likely you will notice any changes early. A family member or friend can help you keep an eye on hard to view areas. Changes in your skin to watch out for, include:

• new spots or moles show up
• an existing mole:
  • changes in some way
  • gets bigger
  • is varied in colour, becomes darker or blotchy/patchy
  • isn't an even shape and has irregular edges
  • becomes raised and waxy or scaly
  • itches or bleeds or is sore
  • forms a lump or nodule

Melanomas can look very different from each other, but the one thing they have in common is that they change in appearance. Changes may seem minor, but they should not be ignored.

If you notice any changes to your skin see your GP. Cancers that are diagnosed early can be easier to treat.

There are three main types of skin cancer:

• Basal Cell Carcinoma (BCC)
• Squamous Cell Carcinoma (SCC)
• Melanoma

At least 95% of melanoma and 98% of non-melanoma skin cancers are caused by overexposure to UV from the sun.

BCCs and SCCs are the most common skin cancers and are often grouped together and called non-melanoma skin cancers or keratinocyte cancers. These cancers do not usually spread to other parts of the body, although they do require early detection and prompt treatment to prevent this from happening.

BCC and SCC cancers are more common than melanoma and the majority are successfully treated.

Melanoma is more serious and can spread to other parts of your body.

Melanoma is a cancer of the melanocyte cells – the cells in the epidermis of the skin that make colour.

It’s by far the most serious and dangerous type of skin cancer as it can easily spread to other organs in the body.

When it spreads, the cancer extends deeper and can invade healthy tissue such as nearby lymph nodes. It can also get into your bloodstream. This allows it to easily spread to other parts of the body.

So even if a melanoma is cut out, the cancer can reappear months or years later, often in your lungs, liver or brain.

A melanoma only 1mm deep can get into your bloodstream and spread, so detecting melanoma early is important.

The good news is that nearly all melanoma is preventable by avoiding overexposure to UV radiation. Melanoma develops on the skin so, by checking your skin and being aware of any changes, most melanomas can be detected before they have the chance to spread.

Treatments are improving and survival rates for melanoma are high in Australia. However, preventing melanoma altogether is better than needing treatment.

Find out more about preventing skin cancer >

Your skin is your body's largest organ. It protects your body from the outside world, including sunlight, heat, injury and infection.

It helps regulate your body's temperature, stores fat and water, and produces Vitamin D.

The layers of your skin

Your skin is made up of two layers:

• The dermis: This is the innermost layer. It’s full of blood and lymph vessels, hair follicles and glands (for instance, those that produce sweat).
• The epidermis: The top layer that you can see. It’s made up of flat, scale-like cells called squamous cells.

Melanin: Your skin’s colour

Melanin is what gives your skin its natural colour—the colour you were born with. It's the distribution of melanin in the skin which results in different skin types, giving us either lighter or darker skin tones or skin with freckles or moles.

Melanocytes, found in the lower part of the epidermis, are the cells that produce melanin. This is also where melanoma, the most serious type of skin cancer, occurs.

How much melanin you have and how it is distributed in response to ultraviolet radiation (UVR) influences whether we are likely to develop skin cancer. Where we live and what we do also play a large role.

While melanomas can occur in anyone, some people are at much greater risk. People who should take particular care have:

• Fair skin—people with fair skin are particularly susceptible to melanoma, especially if their skin burns quickly. People with fair skin are likely to have red or light-coloured hair and blue or green eyes; their skin is also likely to freckle, and they may have many moles.
• Experienced short bursts of extreme exposure—this may be especially harmful in the development of melanoma so extreme care should be taken if you spend most of your days indoors and are then outside on weekends or during holidays.
• Experienced multiple sun burns during childhood to early adulthood—this is when you’re most likely to cause damage to your skin.

Keratinocyte cancers (SCC and BCC) are more common in people with prolonged and intensive exposure to UV radiation especially if they have fairer skin, as they get older if they work outdoors or play outdoor sports. People with a previous experience of skin cancer are at greater risk of further cancers appearing and there are other medical risk factors, for example because of immunosuppression or use of photosensitising medications.

Growing up in Australia means a greater risk of developing skin cancer. In fact, two out of three Australians will be treated for skin cancer during their lifetime.

This is a rarer type of melanoma accounting for only 1-3% of all melanoma diagnoses in Australia which occurs on the palms of the hands, soles of the feet or underneath the nails. It is the most common type of melanoma experienced by people with darker skin tones.

Preventing acral melanoma: It is unclear what causes the cells to become cancerous or if sun exposure/UV radiation plays a role. Early detection is important. 

You can also view our page on detecting skin cancer early.

What is Uveal (eye) melanoma? Uveal melanoma (also known as ocular or eye melanoma), is the most common form of eye cancer.

Preventing uveal melanoma: Protecting yourself from UV/solar radiation can reduce your risk but the cause of uveal cancer is not always known. For more information please see: Ocular (eye) melanoma cancer | Cancer Council.

Lip cancer: Lip cancer is not considered a skin cancer but a mouth cancer - however cancers of the lips are commonly associated with UV sun exposure and therefore preventing exposure when the UV index is above 3 is important (as with skin cancer prevention). For more information on mouth cancer.