Did you know 2 in 3 of us will be diagnosed with skin cancer by age 70? With one Australian losing their life to melanoma every five hours, it's important that we know what skin cancer is - including the various types - and what signs to look out for to keep our skin healthy and safe.

This is what you need to know about skin cancer.

What is skin cancer?

Most skin cancers are locally destructive cancerous growths on the skin. They originate from the cells in the outer layers of the skin, called the epidermis. There are various types of skin cancers that grow in different cell types.

Some types of skin cancer grow larger on the skin and cause disfigurement and pain. Aggressive skin cancers like melanoma can quickly spread to other organs in the body and become deadly.

What causes skin cancer?

The vast majority of skin cancers are caused by exposure to the sun's ultraviolet (UV) radiation, which damages the cells and causes tanning, sunburn, pigmentation, freckles, and potentially turns those cells cancerous. Skin cancers will often develop years after sun exposure has occurred. Solarium use also significantly increases your chances of growing skin cancer.

Some skin cancers can also appear in areas that haven't been exposed to the sun. Melanoma can be hereditary; if your parent, sibling or child has had a melanoma, your own risk increases significantly.

What does skin cancer look like?

Skin cancer can look like anything! It usually appears as a new or changing lesion on your skin that stands out from the others. See what skin cancer looks like here.

Did you know?
Over 1.1 million skin cancers are treated every year in Australia.

What types of skin cancer are there?

Basal cell carcinoma

Basal cell carcinoma (BCC) is the most common type of skin cancer, originating in the skin cells and most often appearing on very sun-exposed areas such as the face, ears and torso, especially in older people. Most BCCs are caused by exposure to UV radiation from the sun.

Signs of basal cell carcinoma include:

• A shiny pink, red, pearly, or translucent bump
• Pink skin growths or lesions with raised borders that are crusted in the centre
• Raised red patch of skin that may crust or itch, but is usually not painful
• A white, yellow, or waxy area with a poorly defined border that may resemble a scar  

BCC is usually treated successfully with minor surgery and rarely spreads beyond its original site, but it can be locally destructive to surrounding tissue if not treated in a timely manner.

Squamous cell carcinoma

Squamous cell carcinoma (SCC) is the second most common type of skin cancer and it originates in the skin cells. SCC is common on sun-exposed areas such as the ears, face, scalp, neck, and hands, where sun damage (like wrinkles and age spots) is most common. Most SCCs are caused by exposure to the sun's UV rays.

Signs of squamous cell carcinoma include:

• Persistent, scaly red patches with irregular borders that may bleed easily
• Open sore that does not go away
• A raised growth with a rough surface that is indented in the middle
• A wart-like growth

SCC can be very painful, causing local tissue destruction if not treated early. It can also spread to other areas of the body and sometimes become fatal.

Did you know?
Actinic keratoses (also called solar keratoses) are a type of pre-cancerous skin spot. If left untreated, up to 10 per cent of actinic keratoses develop into SCC. They appear as scaly, crusty lesions, often on the face, scalp and hands, and are caused by damage from UV radiation. They can usually be treated with topical creams.

Melanoma

Melanoma makes up less than one per cent of all skin cancers, but causes nearly 100 per cent of skin cancer deaths. These cancers arise from the pigment-producing cells of the skin called the melanocytes. Melanoma can occur anywhere on the body and typically looks asymmetrical (meaning they tend to have an irregular shape), has irregular borders, changes colour, and noticeably grows.

See the ABC guide to melanoma detection here.

Melanoma is best treated with surgery when found early, but can spread to other areas of the body within weeks or months, making it much harder to treat, and can become deadly.

Who is at higher risk of skin cancer?

You are at increased risk for developing skin cancer if you:

• are aged over 40
• have had multiple sunburns
• have pale skin, fair hair or blue eyes
• have a large number of freckles or moles
• have had skin cancer before
• have skin spots that look different to the others
• often enjoy outdoor activities or work outdoors
• bleed easily, even with little abrasion
• have ever used a tanning bed

How is skin cancer treated?

The method of treatment depends on the location and size of the skin cancer and your own health.

Topical medications

Some superficial skin cancers can be treated with creams, gels and solutions such as imiquimod (which stimulates the body's immune system to attack the cancer) and fluorouracil, a chemotherapy drug. Side effects of topical treatments include redness, inflammation and irritation.

Curettage and cautery

The area is numbed with a local anaesthetic and is repeatedly scraped with a curette before the edge is cauterised with an electric needle. It is a fast, easy, and relatively inexpensive treatment for skin cancer, but can leave an unsightly scar and has a recurrence rate as high as 15 per cent.

Surgical excision

For skin cancer surgery, a portion of tissue including the tumour is surgically removed and then the wound is closed with stitches. For large skin cancers, skin grafts or flaps are needed to close the wound. Surgery offers a cure rate of more than 90 per cent and the specimen can be examined to ensure all cancerous cells have been successfully removed.

Radiation therapy

10 to 15 treatment sessions deliver a high dose of radiation to the tumour and surrounding skin. This form of treatment is useful for those unable to undergo surgery, such as elderly people. The advantage of radiation therapy is that there is no cutting involved; however, radiation scars look worse over time.

Combination therapy

In cases where a melanoma or invasive SCC has spread to other organs in the body, a combination of treatments can be used. This may include surgery to remove the tumour from the lymph nodes or organs, chemotherapy, radiation therapy, or even immunotherapy in which medication stimulates the immune system to fight off cancer cells.

When should I see a doctor about my moles?

Outside of your annual skin cancer check, you should see a doctor if any mole:

• changes shape, colour, or size;
• becomes crusted, itchy, flaky, or bleeds easily;
• won’t heal after a few weeks;
• becomes raised or irritable; or
• appears anew, especially if you are over the age of 30.