What is skin cancer and melanoma?

Skin cancer is a disease that occurs when your skin cells grow abnormally, usually from too much exposure to ultraviolet (UV) radiation from the sun.

This uncontrolled growth of abnormal cells forms a tumour in the skin. Tumours are either benign (non-cancerous), or malignant (cancerous tumours that can spread through the body, causing damage).

Skin cancer is the most common type of cancer: each year, more than 15,000 Australians are diagnosed with a melanoma and over a million new cases of non-melanoma skin cancers are treated. Skin cancer is mostly preventable, and there are effective treatment options available.

Skin cancers are named according to the cells in which they form. There are 3 main types:

• Basal cell carcinoma (BCC) begins in the lower layer of cells of the epidermis — your outer layer of skin. These tend to grow slowly, and rarely spread to other parts of the body.
• Squamous cell carcinoma (SCC) grows from the flat cells found in the top layer of your epidermis. SCC can grow quickly on the skin over several weeks or months. Bowen’s disease is an early form of SCC that hasn’t grown beyond the top layer of skin.
• Melanoma grows from cells called melanocytes — cells that give your skin its colour. Melanoma is the rarest type of skin cancer (accounting for 1 to 2% of cases) but is considered the most serious because it can spread quickly (metastasise) throughout the body.

BCC and SCC are also called non-melanoma skin cancers. About 2 in 3 non-melanoma skin cancers are BCC, and around 1 in 3 are SCC. There are other types of non-melanoma skin cancers, but they are rare.

What are the symptoms of skin cancer?

Skin cancers first appear as a spot, lump or scaly area on the skin, or a mole that changes colour, size or shape over several weeks or months. These changes can appear anywhere on the body, particularly areas frequently exposed to the sun. Skin cancers may bleed and become inflamed, and can be tender to the touch.

There are certain characteristics to look for in spots and moles. Remember the ‘ABCDE’ of skin cancer when checking your skin:

• Asymmetry — does each side of the spot or mole look different to the other?
• Border — is it irregular, jagged or spreading?
• Colours — are there several, or is the colour uneven or blotchy?
• Diameter — look for spots that are getting bigger
• Evolution — is the spot or mole changing or growing over time?

Changes may include a spot or lump that grows quickly and is thick, red, scaly or crusted, or an area that is:

• scaly
• shiny
• pale or bright pink in colour

See your doctor if you notice any new spots or an existing spot that changes size, shape or colour over several weeks or months. Your doctor can help you distinguish between a harmless spot such as a mole, and a sunspot (actinic keratosis) or irregular mole (dysplastic naevus) that could develop later into skin cancer.

What causes skin cancer?

Almost all skin cancers in Australia are caused by too much exposure to UV radiation. This is the part of sunlight that causes tanning, sunburn and skin damage over time. UV radiation also comes from non-natural sources such as sun beds (solariums).

While anyone can get skin cancer, it gets more common as you get older. The risk is also higher if you have:

• previously had skin cancer or have family history of skin cancer
• fair or freckled skin, particularly if it burns easily or doesn’t tan
• red or fair hair and light-coloured eyes
• a weakened immune system (such as after surgery, or from an ongoing condition like leukaemia)
• sunspots or irregular moles on your body
• worked, played sport or spent leisure time in the sun
• actively tan or use sun beds

If you have olive or dark skin, your skin produces more melanin, which protects to some extent against UV radiation. However, it’s still possible for you to develop skin cancer.

When should I see my doctor?

It’s important to check your own skin regularly to find any new or changing spots.

See your doctor or dermatologist straight away if you notice any changes to your skin, such as:

• an ‘ugly duckling’ — a spot that looks or feels different to any others
• a spot that changes size, shape, colour or texture over time
• a sore that doesn’t go away after a few weeks
• a sore that itches or bleeds

How is skin cancer diagnosed?

Your doctor or dermatologist will ask about your symptoms and family history. They will then conduct a physical examination by looking at your skin to identify any suspicious spots using a dermatoscope (a magnifying glass for the skin).

It’s not always possible to tell from looking at it whether a spot or lump is cancerous or not. Your doctor or dermatologist may take a skin biopsy to help with a diagnosis. This is where a part or all of your spot is removed and sent for further study under a microscope.

Some smartphone apps allow you to photograph your skin and compare photos over time. While they can be a good reminder to check your skin and record details, they shouldn’t replace a visit to the doctor. See a doctor if you’re concerned about any spots or moles on your skin.

Diagnosing melanoma

If your doctor suspects melanoma, a biopsy will be taken. Your doctor may also check nearby lymph nodes.. The samples are then sent for testing to check if your spot is a melanoma.

Melanomas are graded according to how far they have spread throughout the body.

• Stage 0-II refers to early melanoma.
• Stage III melanoma (regional) has spread to nearby lymph nodes, skin or tissues.
• Stage IV melanoma (advanced, metastatic) has spread to other parts of the body.

How is skin cancer treated?

Skin cancer treatment depends on the type, its size and location and whether it has spread elsewhere. Most skin cancers are successfully treated — especially if detected early.

Surgical treatments

Surgery is the most common treatment for skin cancer. Some cancers are completely removed during the biopsy. If cancer cells are found at the margin (edges of the sample removed), you may need further treatment. Large skin cancers may require a skin graft to cover the wound.

Most basic skin cancer surgeries can be performed by your doctor. When removing a suspected cancer, your doctor will also cut out some nearby skin (the margin) for testing.. If they discover cancer cells in the margin, you may need further surgery or radiation therapy.

For cancers in areas hard to manage surgically (such as near the eyes, nose, lips or ears), a technique called Mohs surgery (microscopically controlled excision) may be used.

Other surgical methods include curettage (removal of tissue with a spoon shaped instrument with a sharp edge) and electrodessication (cautery — burning to remove tissue). These methods are usually performed by a dermatologist.

Other treatments

• Topical treatments: These include applying cream, lotion or gel to the skin. The treated skin usually blisters, peels or cracks for several weeks — this is a sign the cancer cells are being destroyed, and new, healthy skin will replace it.
• Cryotherapy: Liquid nitrogen is used to freeze and remove sunspots and some small BCCs.
• Photodynamic therapy: This involves applying cream that makes skin cancer sensitive to light, and then using a light source on the spot.
• Radiation therapy (radiotherapy): Radiation is used to destroy cancer in areas less suitable to surgery (such as the face). It may also be used after surgery to reduce the likelihood of the cancer returning.
• Lymph node biopsy: Your doctor may recommend removing the lymph nodes which are close to the skin cancer to reduce the risk of cancer returning or spreading. This can also help you and your doctor understand how far the cancer has spread.

Are there complications of skin cancer treatment?

Most skin cancer treatments involve some localised damage to surrounding healthy skin such as swelling, reddening or blistering of the skin where the cancer is removed. Your doctor will explain any specific risks, which may include:

• pain or itching where the skin has been treated, or if lymph nodes have been removed
• scarring or changes to skin colour after a skin cancer has been removed
• bleeding during or after surgery for more complicated skin cancers
• reactions to medicines used in treatment or surgery
• lymphoedema — if your lymph nodes have been removed your neck, arm or leg may swell with fluid

It’s best to manage complications as early as possible, so ask your doctor or other members of your health team for advice.

Can skin cancer be prevented?

Skin cancer is almost entirely preventable. Making sun protection a part of your life, avoiding sunburn, and checking your skin regularly will help prevent further damage to your skin.

Protect your skin from UV radiation and help prevent skin cancer by following these steps:

• Slip on sun-protective clothing: cover your shoulders, neck, arms, legs and body.
• Slop on sunscreen that’s rated SPF 30+ or higher, broad-spectrum and water resistant.
• Slap on a hat that shades your face, neck and ears.
• Seek shade under trees, umbrellas and buildings from direct sunlight and reflective surfaces.
• Slide on sunglasses that wrap around your face to protect your eyes and surrounding skin.
• Stay away from sun lamps, solariums or sunbeds, because they have dangerous levels of UV radiation.

UV radiation from the sun varies depending on time of day, season, where you live and cloud coverage. Protect your skin whenever UV Index levels are above 3. Use Cancer Council Australia’s free SunSmart app to check the UV Index for your area any time.

While using fake tanning cream isn’t harmful to your skin, it offers no protection from UV radiation. You still need to protect yourself from the sun.

Isn’t sun exposure important to ensure I get enough vitamin D?

Most Australians will get enough vitamin D even with sun protection at UV level 3 or above. Babies and children should be protected from the sun, since they are particularly vulnerable to UV radiation harm.

If the UV level is below 3, you should spend some time outside in the middle of the day to help your body produce enough vitamin D.

Some people are at a higher risk of vitamin D deficiency:

• people with a history of skin cancer or at high risk of skin cancer
• people who wear concealing clothing
• naturally very dark-skinned people
• people who spend long hours indoors, especially people who are housebound or live in a care home
• older adults
• people with obesity
• babies and infants of vitamin D deficient mothers

If you are at risk of vitamin D deficiency, it’s a good idea to discuss this with your doctor, who may recommend a supplement.