Skin cancer is the uncontrolled growth of abnormal cells in the skin.
Learn more about:
The skin
The skin is the largest organ of the body. It acts as a barrier to protect the body from injury, control body temperature and prevent loss of body fluids. The 2 main layers of the skin are the epidermis and dermis.
Epidermis
The epidermis is the top, outer layer of the skin. It contains 3 main types of cells:
| Squamous cells | These flat squamous cells are packed tightly together to make up the top layer of skin. They form the thickest layer of the epidermis. |
| Basal cells | These block-like basal cells make up the lower layer of the epidermis. The body makes new basal cells all the time. As they age, they move up into the epidermis and flatten out to form squamous cells. Both basal and squamous cells are keratinocyte cells, which is why non-melanoma skin cancers are sometimes called keratinocyte cancers. |
| Melanocytes | These cells sit between the basal cells and produce a dark pigment called melanin that gives skin its colour. When skin is exposed to ultraviolet (UV) radiation, melanocytes make melanin to try to protect the skin from getting burnt. Melanocytes are also found in non-cancerous spots on the skin called moles or naevi. |
Dermis
This layer of the skin sits below the epidermis. The dermis is made up of fibrous tissue and contains the roots of hairs (follicles), sweat glands, blood vessels, lymph vessels and nerves.
The layers of the skin
Types of skin cancer
The 3 main types are:
- basal cell carcinoma (BCC) – about 2 out of 3 skin cancers
- squamous cell carcinoma (SCC) – about 1 in 3 skin cancers
- melanoma – about 1 in 100 skin cancers.
| BCC and SCC | These are also called non-melanoma skin cancer or keratinocyte cancer. They are far more common than melanoma and make up about 99% of skin cancers. Find out more about each type. |
| Melanoma | This starts in the melanocytes and makes up 1–2% of all skin cancers. It is the most serious form of skin cancer because it is more likely to spread to other parts of the body, especially if not found and treated early. This section is only about non-melanoma (keratinocyte) skin cancers. For more on this, see Melanoma. |
| Rare types of skin cancer | These include Merkel cell carcinoma and angiosarcoma. They are treated differently from BCC and SCC. Call Cancer Council 13 11 20 for more information. |
What causes skin cancer?
Over 95% of skin cancers are caused by exposure to UV radiation. When unprotected skin is exposed to UV radiation, how the cells look and behave can change.
Across Australia, the UV levels can do damage to unprotected skin most of the year, not just in warmer months. Even when the UV levels are moderate they can still do damage. UV radiation can’t be seen or felt. It isn’t related to the temperature or whether it’s sunny or cloudy. UV radiation can cause sunburn; premature skin ageing; and damage to skin cells, which can lead to skin cancer.
You can’t always see sun damage that’s happened to the skin – and it can happen long before you get sunburnt or develop a tan. The damage also adds up over time and can’t be reversed.
Find out how to protect yourself from the sun and prevent skin cancer from occurring.
How common is skin cancer?
Australia has one of the highest rates of skin cancer in the world. About 2 out of 3 Australians will be diagnosed with some form of skin cancer before the age of 70.
Non-melanoma (keratinocyte) skin cancer is the most common cancer diagnosed in Australia. Over 1 million treatments are given each year in Australia for non-melanoma skin cancers. BCC can develop in young people, but it is more common in people over 40. SCC occurs mostly in people over 50.
Who is at risk?
Anyone of any age can develop skin cancer but it becomes more common as you get older.
Many factors can increase your risk of skin cancer, including having:
- pale or freckled skin, especially if it burns easily and doesn’t tan
- red or fair hair and light-coloured eyes (blue or green)
- unprotected exposure to UV radiation, particularly a pattern of short, intense periods of sun exposure and sunburn, such as on weekends and holidays
- actively having tanned, sunbaked or used solariums
- worked outdoors or spent a lot of time outside (e.g. gardening or golfing)
- been exposed to arsenic
- a weakened immune system – this may be from having leukaemia or lymphoma or using medicines that suppress the immune system (e.g. for rheumatoid arthritis, another autoimmune disease or for an organ transplant)
- lots of moles, or lots of moles with an irregular shape and uneven colour
- a previous skin cancer or a family history of skin cancer
- certain skin conditions such as sunspots, because they show that you have had a lot of skin damage from exposure to the sun
- smoked cigarettes, as smoking has been linked to a possible increase in skin cancer risk.
People with brown, black, olive or very dark skin colour often have more protection against UV radiation because their skin produces more melanin than fair skin does. However, they can still develop skin cancer.
For an overview of what to expect at every stage of your cancer care, visit Cancer Care Guides – Basal and squamous cell carcinoma. This is a short guide to what is recommended, from diagnosis to treatment and beyond.
→ READ MORE: The signs of skin cancer
More resources
A/Prof Victoria Mar, Director, Victorian Melanoma Service, Alfred Hospital and Monash University, VIC; Tracey Bilson, Consumer; Raelene Buchan, Consumer; Alison Button-Sloan, Consumer; Dr Margaret Chua, Radiation Oncologist, and the Skin Radiation Oncology team, Peter MacCallum Cancer Centre, VIC; Prof Anne Cust, Deputy Director, The Daffodil Centre, The University of Sydney and Cancer Council NSW, Chair, National Skin Cancer Committee, Cancer Council, and faculty member, Melanoma Institute Australia; A/Prof Paul Fishburn, Skin Cancer Doctor, Norwest Skin Cancer Centre, NSW and Faculty of Medicine, University of Queensland; Danielle Goss, Melanoma Clinical Nurse Specialist, Amie St Clair Melanoma (part of Melanoma Institute Australia), Wagga Wagga, NSW; Louise Pellerade, 13 11 20 Consultant, Cancer Council WA: Dr Shireen Sidhu, Head of Dermatology, The Royal Adelaide Hospital, SA; Dr Amelia Smit, Research Fellow – Melanoma and Skin Cancer, The Daffodil Centre, The University of Sydney and Cancer Council NSW; Dr Tony Tonks, Plastic and Reconstructive Surgeon, Canberra Plastic Surgery, ACT.
View the Cancer Council NSW editorial policy.
