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What is skin cancer?

Skin cancer is the uncontrolled growth of abnormal cells in the skin.

Types of skin cancer

The three main types of skin cancer are basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma. BCC and SCC are also called non-melanoma skin cancer or keratinocyte cancers.

Rare types of non-melanoma skin cancer include Merkel cell carcinoma and angiosarcoma. They are treated differently from BCC and SCC. Call Cancer Council 13 11 20 to find out more about rarer skin cancers.

Basal cell carcinoma (BCC) – This starts in the basal cells of the epidermis. It makes up about 70% of non-melanoma skin cancers.

BCC grows slowly over months or years and rarely spreads to other parts of the body. The earlier a BCC is diagnosed, the easier it is to treat. If left untreated, it can grow deeper into the skin and damage nearby tissue, making treatment more difficult.

Having one BCC increases the risk of getting another. It is possible to have more than one BCC at the same time on different parts of the body.

Squamous cell carcinoma (SCC) – This starts in the squamous cells of the epidermis. It makes up about 30% of non-melanoma skin cancers.

SCC tends to grow quickly over several weeks or months. If left untreated, SCC can spread to other parts of the body. This is known as invasive SCC. SCC on the lips and ears is more likely to spread.

Melanoma – This starts in the melanocyte cells of the skin. It makes up 1–2% of all skin cancers.

Although melanoma is a less common type of skin cancer, it is considered the most serious because it grows quickly and is more likely to spread to other parts of the body, such as the lymph nodes, lungs, liver, brain and bones, especially if not found early. The earlier melanoma is found, the more successful treatment is likely to be.

Download our booklet ‘Understanding Melanoma’

Other type of skin cancer

Squamous cell carcinoma in situ, or Bowen’s disease, is an early form of skin cancer that is only in the top layer of the skin (epidermis). It looks like a red, scaly patch and can develop into invasive squamous cell carcinoma if left untreated. The diagnosis and treatment of squamous cell carcinoma in situ is similar to BCC and SCC.

Click on image to enlarge

What about other skin spots?

Some spots that appear on the skin are not cancerous.

Sunspots (actinic or solar keratoses) – Anyone can develop sunspots, but they occur more often in people over 40. They usually appear on skin that’s frequently exposed to the sun, such as the head, neck, hands, forearms and legs. Sunspots are a warning sign that the skin has had too much sun exposure, which can increase the risk of developing skin cancer.

Dysplastic naevi – People with many irregular moles (dysplastic naevi) have a greater risk of developing melanoma. The risk increases with the number of moles that a person has.

Moles (naevi) – A mole (naevus) is a normal skin-growth that develops when melanocytes grow in groups. Moles are very common. Some people have many moles on their body – this can run in families. Overexposure to the sun, especially in childhood, can also increase the number of moles. People with large numbers of normal moles can have a higher risk of melanoma.

Click on image to enlarge

How common is skin cancer?

Australia has one of the highest rates of skin cancer in the world. Skin cancer is the most common cancer diagnosed in Australia. About two in three Australians will be diagnosed with some form of skin cancer before the age of 70.

Almost 980,000 new cases of BCC and SCC are treated each year. BCC can develop in young people, but it is more common in people over 40. SCC occurs mostly in people over 50.

More than 13,000 people are diagnosed with melanoma in Australia every year. Australia and New Zealand have the highest rates of melanoma in the world.

Featured resource

Understanding Skin Cancer

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Learn more about the Skin Cancer Fund and the work we do in skin cancer research, prevention and support.

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This information is reviewed by

This information was last reviewed in January 2020 by the following expert content reviewers: Prof Diona Damian, Dermatologist, The University of Sydney at Royal Prince Alfred Hospital, and Associate, Melanoma Institute of Australia, NSW; Dr Annie Ho, Radiation Oncologist, Genesis Care, Macquarie University, St Vincent’s and Mater Hospitals, NSW; Rebecca Johnson, Clinical Nurse Consultant, Melanoma Institute of Australia, NSW; Shannon Jones, SunSmart Health Professionals Coordinator, Cancer Council Victoria; Liz King, Skin Cancer Prevention Manager, Cancer Council NSW; Roslyn McCulloch, Consumer; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Paige Preston, Policy Advisor, Cancer Prevention, Health and Wellbeing, Cancer Council Queensland; Dr Michael Wagels, Plastic and Reconstructive Surgeon, Princess Alexandra Hospital, QLD. Thanks also to Sydney Melanoma Diagnostic Centre for providing the dysplastic naevus photograph, and to Prof H Peter Soyer for providing the other photographs. We also thank the health professionals, consumers and editorial teams who have worked on previous editions of this title.