About melanoma skin cancer
Melanoma is a type of skin cancer. It develops in the skin cells called melanocytes.
Melanoma most often develops in areas that have been exposed to the sun. It can also start in areas that don’t receive much sun, such as the eye (uveal or ocular melanoma); nasal passages, mouth and genitals (mucosal melanoma); and the soles of the feet or palms of the hands, and under the nails (acral melanoma).
Learn more about:
- Types of skin cancer
- The skin
- How common is melanoma?
- How do I spot a melanoma?
- The main types of melanoma
- What causes melanoma?
- Who is at risk?
- Having a family history of melanoma
Types of skin cancer
Melanoma is not the only type of skin cancer. Other types of skin cancer include basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). These are known as non-melanoma skin cancers or keratinocyte cancers, and they are far more common than melanoma.
However, melanoma is considered the most serious form of skin cancer because it is more likely to spread to other parts of the body, especially if not found early. The earlier melanoma is found, the more successful treatment is likely to be.
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 the dermis.
Below these is a layer of fatty tissue known as the hypodermis.
The epidermis is the top, outer layer of the skin. It is made up of several sublayers that work together to continually rebuild the surface of the skin. The main sublayers are the basal cell layer and the squamous cell layer.
Basal cell layer – This is the lowest layer of the epidermis. It contains basal cells and cells called melanocytes. The melanocyte cells produce a dark pigment called melanin, which gives skin its colour. When skin is exposed to ultraviolet (UV) radiation, melanocytes make melanin to try to protect the skin from getting burnt. This is what causes skin to tan. When melanocytes cluster together they form non-cancerous spots on the skin called moles or naevi.
Squamous cell layer – This sits above the basal cell layer. Basal cells that have matured move up into the squamous cell layer. Here they are known as squamous cells or keratinocyte cells. Squamous cells are the main type of cell found in the epidermis.
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.
Layers of the skin
How common is melanoma?
Australia and New Zealand have the highest rates of melanoma in the world. Melanoma is the second most common cancer in men and the third most common cancer in women (excluding non-melanoma skin cancers).
Every year in Australia, about 17,800 people are diagnosed with melanoma that has spread into the dermis (known as invasive melanoma). About 27,500 people are diagnosed each year with melanoma that is confined to the epidermis (melanoma in situ).
How do I spot a melanoma?
New moles mostly appear during childhood and through to the 30s and 40s. However, adults of any age can develop new or changing spots. It is important to get to know your skin and check it regularly.
In a room with good light, undress completely and use a full-length mirror to check your whole body. For areas that are hard to see, use a handheld mirror or ask someone to help. It is also a good idea to take a photograph of your moles and spots so that you can compare them to an older image if you notice one has changed.
Look for spots that are new, different from other spots, or raised, firm and growing. Even if your doctor has said a spot is benign in the past, check for any changes in shape, size or colour. If you notice a new or changing spot, get it checked as soon as possible by your doctor.
What are the main types of melanoma?
Melanoma of the skin is known as cutaneous melanoma. There are 5 main subtypes of cutaneous melanoma:
- Superficial spreading melanoma
- Nodular melanoma
- Lentigo maligna melanoma
- Acral lentiginous melanoma
- Desmoplastic melanoma
Superficial spreading melanoma
|How common?||Makes up 55–60% of all melanomas.|
|Who gets it?||Most common type of melanoma in people under 40, but can occur at any age.|
|What does it look like?||Can start as a new brown or black spot that grows on the skin, or as an existing spot, freckle or mole that changes size, colour or shape.|
|Where is it found?||Can develop on any part of the body but especially the area between the shoulders and hip (trunk).|
|How does it grow?||Often grows slowly and becomes more dangerous when it invades the lower layer of the skin (dermis).|
|How common?||Makes up about 10–15% of melanomas.|
|Who gets it?||Most commonly found in people over 65.|
|What does it look like?||Usually appears as a round, raised lump (nodule) on the skin that is pink, red, brown or black and feels firm to touch; may develop a crusty surface that bleeds easily.|
|Where is it found?||Usually found on sun-damaged skin.|
|How does it grow?||Fast-growing form of melanoma, spreading quickly into the lower layer of the skin (dermis).|
Lentigo maligna melanoma
|How common?||Makes up about 10–15% of melanomas.|
|Who gets it?||Most people with this subtype are over 40.|
|What does it look like?||Begins as an enlarging pigmented spot.|
|Where is it found?||Mostly found on sun-damaged skin on the face, ears, neck or head.|
|How does it grow?||May grow slowly and superficially over many years before it grows deeper into the skin.|
Acral lentiginous melanoma
|How common?||Makes up about 1–2% of all cases.|
|Who gets it?||Mostly affects people over 40 with dark skin such as those of African, Asian and Hispanic backgrounds.|
|What does it look like?||Often appears as a colourless or lightly coloured area, may be mistaken for a stain, bruise or unusual wart; in the nails, can look like a long streak of pigment.|
|Where is it found?||Most commonly found on the palms of the hands, on the soles of the feet, or under the fingernails or toenails.|
|How does it grow?||Tends to grow slowly until it invades the lower layer of the skin (dermis).|
|How common?||Makes up about 1–2% of all cases.|
|Who gets it?||Mostly affects people over 60.|
|What does it look like?||Starts as a firm, growing lump, often the same colour as your skin; may be mistaken for a scar and can be difficult to diagnose.|
|Where is it found?||Mostly found on sun-damaged skin on the head or neck, including the lips, nose and ears.|
|How does it grow?||Tends to be slower to spread than other subtypes, but often diagnosed later; sometimes can invade or spread via nerves.|
Other types of melanoma
Some rarer types of melanoma start in other parts of the body. Mucosal melanoma can start in the tissues in the mouth, anus, urethra, vagina or nasal passages. Ocular melanoma can start inside the eye. Melanoma can also start in the central nervous system.
See Ocular melanoma or call 13 11 20 for more information about rarer types of melanoma.
For an overview of what to expect at every stage of your cancer care, visit Cancer Pathways – Melanoma. This is a short guide to what is recommended, from diagnosis to treatment and beyond.
What causes melanoma?
Exposure to ultraviolet (UV) radiation is the cause of most types of skin cancer. If unprotected skin is exposed to the sun when the UV index is 3 or above or to other UV radiation, the structure and behaviour of the cells can change. This can permanently damage the skin, and the damage builds up every time a person spends time unprotected in the sun.
UV radiation most often comes from the sun, but it can also come from artificial sources such as solariums (also known as tanning beds or sun lamps). Solariums are now banned for commercial use in Australia because research shows that people who use solariums have a much greater risk of developing melanoma.
Who is at risk?
Anyone can develop melanoma. The risk is higher in people who have:
- unprotected exposure to UV radiation when the UV index is 3 or above, particularly a pattern of short, intense periods of sun exposure and sunburn, such as on weekends and holidays
- lots of moles (naevi), especially if the moles have an irregular shape and uneven colour
- pale or freckled skin, especially if it burns easily and doesn’t tan
- fair or red hair, and blue or green eyes
- a previous melanoma or other type of skin cancer
- a strong family history of melanoma
- a weakened immune system from using immunosuppressive medicines for a long time.
Family history of melanoma
Sometimes the risk of melanoma runs in families. Often, this is because family members have a similar skin type or a similar pattern of sun exposure in childhood.
About 2% of melanomas are linked to an inherited faulty gene. You may have an inherited faulty gene if 2 or more close relatives (parent, sibling or child) have been diagnosed with melanoma, particularly if they were diagnosed with more than one melanoma, or if they were diagnosed with melanoma before the age of 40.
People with a strong family history of melanoma should use sun protection and check their skin carefully for new moles or skin spots. From their early 20s, they should consider having a professional skin check by a doctor. This may be every year. Discuss the frequency with your doctor.
If you are concerned about your family risk factors, talk to your doctor about referral to a family cancer clinic. Visit Centre for Genetics Education to find a family cancer clinic near you. To learn more, call Cancer Council 13 11 20.
Podcast for people affected by cancer
Prof H Peter Soyer, Chair in Dermatology and Director, Dermatology Research Centre, The University of Queensland, Diamantina Institute, and Consultant, Dermatology Department, Princess Alexandra Hospital, QLD; A/Prof Matteo Carlino, Medical Oncologist, Blacktown and Westmead Hospitals, Melanoma Institute Australia and The University of Sydney, NSW; 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; Prof Diona Damian, Dermatologist, Head of Department, Dermatology, The University of Sydney at Royal Prince Alfred Hospital, NSW, and Melanoma Institute Australia; A/Prof Paul Fishburn, General Practitioner – Skin Cancer, Norwest Skin Cancer Clinic, NSW and The University of Queensland; Claire Kelly, National Support Manager, and Emma Zurawel, Telehealth Nurse, Melanoma Patients Australia; Prof John Kelly, Consultant Dermatologist, Victorian Melanoma Service, The Alfred Melbourne and Monash University, VIC; Liz King, Manager, Skin Cancer Prevention Unit, Cancer Council NSW; Lee-Ann Lovegrove, Consumer; Lynda McKinley, 13 11 20 Consultant, Cancer Council Queensland; Angelica Miller, Melanoma Community Support Nurse, Melanoma Institute Australia incorporating melanomaWA, and Cancer Wellness Centre, WA; Dr Amelia Smit, Research Fellow, Melanoma and Skin Cancer, The Daffodil Centre, The University of Sydney and Cancer Council NSW; Prof Andrew Spillane, Professor of Surgical Oncology, The University of Sydney, The Mater and Royal North Shore Hospitals, NSW, and Melanoma Institute Australia; Kylie Tilley, Consumer; A/Prof Tim Wang, Radiation Oncologist, Crown Princess Mary Cancer Centre, Westmead Hospital, NSW. We also thank the health professionals, consumers and editorial teams who have worked on previous editions of this title.
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