Skin Cancer Explained

Skin Cancer Explained

What is skin cancer?

Skin cancer is the abnormal and uncontrolled growth of skin cells. This is a result of overexposure to ultraviolet light (UV), causing damage to the cells’ DNA. Australia’s location in the southern hemisphere and proximity to the equator results in high UV levels most of the year. Skin cancer accounts for the largest number of cancers diagnosed in Australia each year. Read more skin cancer facts.

The main types of skin cancer are basal cell carcinoma, squamous cell carcinoma and melanoma. Some skin cancers (most commonly melanoma) can spread to other parts of the body. When this happens, it’s called metastasis. Early detection and treatment are the best way to prevent skin cancer from spreading.

Find out what skin cancer can look like in its early stages in this article.

What are the risk factors for skin cancer?

Australasia has the highest rates of skin cancer world-wide. Two in three of us are expected to be diagnosed with some form of skin cancer by the age of 70. Skin cancer doesn’t discriminate. Yet, men tend to get it more often, and have more adverse outcomes, compared to women. According to this report by the Global Coalition for Melanoma Patient Advocacy, men are 10% more like­ly to devel­op melanoma than women and 4% more like­ly to die from melanoma than women.

The best way to take appropriate steps for prevention and early diagnosis is to know the risk factors. Several factors can increase your risk of skin cancer, including:

  • A family/personal history of skin cancer
  • A history of sun damage and UV exposure, such as sunbeds
  • Having fair skin and light-coloured hair
  • A high number of moles

Read more about the risk factors for skin cancer:

Wondering if tattoos can cause skin cancer?

Want to know your skin cancer risk? Take our risk quiz below.

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Types of skin cancer

The main types of skin cancer are:

Basal cell carcinoma and squamous cell carcinoma, among other less common skin cancers, are known as non-melanoma or keratinocyte skin cancer. Non-melanoma skin cancer (NMSC) is the most common cancer diagnosed in Australia, with around 400,000 new cases every year.

Basal cell carcinoma

Basal cell carcinoma is the most prevalent form of skin can­cer. It account­s for about 70% of non-melanoma skin can­cers. It’s also the most frequently occurring skin cancer.

It begins in the skin’s basal cells in the outermost layer of skin (the epidermis). Having one basal cell carcinoma increases the risk of getting another. It’s also pos­si­ble to have more than one basal cell carcinoma at the same time on dif­fer­ent parts of the body. The good news is that most basal cell carcinomas are curable and cause minimal damage when detected and treated early.

FACT: Basal cell carcinoma usually grows slowly. If left untreated it can grow deep into the skin, making treatment more difficult.

Find out more about basal cell carcinoma, including where on the body it most often occurs.

Squamous cell carcinoma

Squamous cell carcinoma is the second most common form of skin cancer. It accounts for around 30% of all skin cancers, if actinic keratoses are excluded from this group. It starts in the squamous cells, in the upper layer of the epidermis.

Squamous cell carcinoma is usually found on areas of the body that get the most sun exposure. This includes the head, neck, hands, forearms, and lower legs. If left unnoticed, squamous cell carcinoma can grow quickly. On a positive note, if found early it is treatable.

FACT: Unlike basal cell carcinoma, which rarely spreads, squamous cell cancer may spread to the lymph nodes and internal organs.

Find out more about squamous cell carcioma, including the signs and how quickly it can spread.


Melanoma also occurs when DNA in the melanocyte cells becomes damaged, most often due to an over exposure of UV radiation. (Sometimes the risk can come from an inherited genetic factor too.) Damage to the cells causes them to reproduce uncontrollably, resulting in melanoma skin cancer.

Melanoma makes up a small proportion of all skin cancer diagnoses (around 3%). However, it is the most serious form of skin cancer. If it’s not found and treated early, it is likely to spread to other parts of the body. Melanoma accounts for 65% of all deaths from skin cancer.

FACT: Only about 25% of melanomas are found in existing moles. About 75% are detected on normal-looking skin without a pre-existing mole.

Find out more about the stages of melanoma and the survival rates.

Skin cancer symptoms

The signs of skin cancer can vary between individuals and depending on the type of skin cancer. Symptoms tend to develop on areas of the skin most often exposed to sunlight. However, some skin cancers appear on areas of the body rarely exposed to UV light.

The best way to spot skin cancer symptoms early is to regularly check your skin for changes. Key things to watch out for include:

What does skin cancer look like?

Basal cell carcinoma is the most common skin cancer. It can appear as a round flesh-coloured growth, as a pale or bright pink patch or skin, or as a pearl-like lump. But the truth is, skin cancer can look different from person to person.

To gain a better understanding of the signs, it can be useful to look at pictures of skin cancer. This gallery of skin cancer images from the Skin Cancer Foundation is a helpful resource.

Want to know more on this topic? Check out these articles

What does skin cancer look like?

Your guide to spotting skin cancer

Types of moles (how to know if they’re suspicious or not)

Sunspot or skin cancer: how to tell them apart

Sunspot, freckle, mole: what’s the difference?

How is skin cancer diagnosed?

More than 400,000 Australians are diagnosed with skin cancer every year. Skin cancers are diagnosed on what they look like clinically, dermatoscopically and histologically/microscopically.

There are no specialised tests that definitively confirm the diagnosis of a cancer. Many skin cancers are diagnosed through a skin examination with the aid of a dermatoscope. If it’s not possible to tell if a suspicious lesion is cancerous or not, a biopsy will be taken. This is where a small tissue sample is taken and reviewed under a microscope.

Skin examination

This involves a thorough skin check or mole check to see if any changes may be cancerous, typically performed by a trained professional at an Australia skin cancer clinic, using a dermatoscope.

A dermatoscope assists in early diagnosis. This can mean the difference between a simple excision and extensive systemic treatment.

Skin biopsy

A biopsy is a quick and simple procedure done under local anaesthetic. Usually, the entire mole and some of the healthy surrounding tissue is removed. In some cases, a small piece of tissue from the spot is removed for further microscopic examination and diagnosis.

Skin cancer treatments

Skin cancer treatment options will depend on the type of cancer. Treatment choice can also be influenced by the size, location, and depth of the tumour, as well as whether it has spread or not. Some people may receive a single treatment, others may require a combination.

The most common skin cancer treatment is surgical removal. This is where the mole or skin lesion and some of the surrounding ‘healthy’ tissue is removed. This is a minimally invasive surgery, usually done under local anaesthetic. If all the cancer is removed, this may be the only treatment you’ll need. Other skin cancer treatments may include:

  • Topical medications
  • Cryotherapy—uses liquid nitrate to freeze the mole or skin lesion
  • Photodynamic therapy—a combination of light and topic medication
  • Radiation—uses high-energy x-rays to kill the cancerous skin cells

Want to know more on this topic? Check out these articles

Your guide to skin cancer treatment (and when they’re used)

Topical treatments for skin cancer

How to care for your skin after skin cancer surgery

Preventing skin cancer

The two most important things you can do to prevent skin cancer is to practise sun safety and get a regular skin check.

Sun protection

Ultraviolet (UV) radiation from the sun and other sources, such as sunbeds, causes 95%+ of all skin cancers. Sun damage is accumulative. The more sunburns you have, the greater your risk for skin cancer. According to the Skin Cancer Foundation, more than five sunburns may double your risk of developing melanoma. Protecting your skin against the sun’s UV rays can significantly reduce your skin cancer risk.

A common misconception is that sunscreens provide a means to escape the risk of skin cancer.  Sunscreen will decrease the risk, but current sunscreens will only provide temporary and partial protection.

Spending time in the sun when the UV index is low, using clothing or shade and sunscreen as the last line of defence is still the best way to prevent skin cancers.

Skin checks

Regular (annually or as directed by your GP or skin specialist) skin checks are an essential element of skin cancer early detection. Getting to know your skin is the best way to spot new or changed moles. And yet, only 11% of people have their moles checked by a skin specialist at MoleMap skin cancer clinic, at least once a year.

Want to know more on this topic? Check out these articles

When should you get a skin check?

Who’s the best person to check for skin cancer?

Does vitamin B3 help protect against skin cancer?

Why we offer free spot checks with our Full Body MoleMap.

Dr. Franz Strydom
Board member and Censor Skin Cancer College of Australasia
MB ChB. BSc. Hons BSc (Med Sci) MSc. (Med Sci) FRNZCGP FSCCA

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