Sun damage, the beginning!
The sun is as essential to life as water and oxygen. It keeps us warm, gives us
energy by driving the food chain from which we get our food, and helps to maintain the habitats we live in. It also has a psychological effect; sunlight actually makes us feel good. Unfortunately, there’s a downside. The ultraviolet light in sunlight damages the DNA in our skin causing skin cells to mutate and grow into cancers. Australia has the highest incidence of skin cancer in the world with one in two Australians developing a skin cancer at some time in their lives.
Most damage occurs in the first 15-16 years of life, however, prevention past this time period can help minimise the extent of the cancer.
What is a Sun Spot?
The most common sign of a ‘sun spot’ is a Solar keratoses (also known as actinic keratoses). They look and feel like a rough, reddened, scaly, flaky or crusty patches on the skin that are caused by excessive exposure to Ultraviolet Radiation (UV rays), usually over a long period of time. They are seen in all skin types, even people with “strong” or olive skin. They are now considered to be pre-cancerous changes – that is, eventually a proportion of them will progress into Squamous Cell Carcinoma.
This is a cancer that can spread through the body, and does sometimes kill people.
How do I know if my Sun Spot is dangerous?
The exact number of sunspots that will turn into a skin cancer is not known – it is thought to be about 10%, although experts differ in their estimates, from 0.01% to 100%!
It is not possible to look at a group of sunspots and predict which ones will become cancer, it is far better and safer to treat the damaged skin cells than to wait and watch.
Sometimes a sunspot will give clues, such as growing rapidly, becoming red, scabby/bleeding, thickened or tender especially when squeezed. Such a spot should be partly or completely removed to be checked under the microscope by a pathologist, and then treated appropriately if it is a cancer.
Should I see a doctor?
Sometimes a simple red scaly patch that looks like “just a sunspot” can actually be something far worse. This is why it is so important to see your Gp or get referred to a skin specialist – a dermatologist.
Can Sun Spots be treated?
Actinic keratoses can be treated in many ways: freezing, creams, Photo Dynamic Therapy (PDT) and when necessary excision can be used. Or some cases can be monitored rather than removed.
We look at patients with actinic keratoses in three different circumstances:
- Person with one or two actinic keratoses
- Person with 10 or 20 actinic keratoses
- Person with so many that one almost merges with others surrounding it
In the first situation it is very common to treat the odd actinic keratosis with cryotherapy (liquid nitrogen).
When there are greater numbers, freezing is still the most common treatment. Sometimes thicker or larger lesions are biopsied or excised to ensure they are not invasive Squamous Cell Carcinomas.
When a large skin area appears to be one actinic keratosis after another, we call this a “field effect”. In this situation, creams and PDT are used more often in our management choices.
Types of Skin Cancers
There are three types of commonly encountered skin cancer, named after the
type of skin cell from which they are derived.
Basal cell carcinoma (BCC)
Basal cell carcinomas are the most common type, accounting for about 80 per
cent of all skin cancers. BCCs are found most commonly found on the ears, nose,
and other exposed parts of the body – especially the face and neck. They
generally do not spread beyond the skin, but when neglected, they can
penetrate deeply producing a destructive ulcer. For this reason, they should be removed.
This is usually a minor surgical procedure under local anaesthetic by a GP, a dermatologist or a surgeon.
Some types of BCCs, after assessment by a dermatologist can alternatively be removed by curettage and cryosurgery ( freezing with liquid nitrogen spray).
Squamous cell carcinoma (SCC)
Squamous cell carcinomas arise from the outer layers of the skin. They are less
common than basal cell carcinomas, but are more dangerous because they can
spread to other parts of the body. They appear in areas most commonly
exposed to the sun – the head, neck and upper back and extremities. As they
grow, SCCs can spread to lymph nodes (under the armpits, in the groin or in the
neck, for example) or via the bloodstream to other organs if left untreated.
For this reason they must be surgically removed.
Melanoma
Melanoma (cancerous mole) is the fifth most common cancer in Australia (after non-melanocytic skin cancers, colorectal, prostate and breast cancer), and is the most common cancer in men and women aged 15 to 44 years. It is also the deadliest form of skin cancer and in one third of cases, may arise from a pre-existing mole.
Since it is known to run in families, genes are thought to play a role with some people inheriting a genetic predisposition to the disease. A melanoma can arise anywhere in the body, not just on sites exposed to the sun. Sometimes it can arise on the sole of the foot, the palm of the hand or under the nails. It is usually dark and can grow quickly and spread to nearby lymph nodes, or via the bloodstream to distant organs like the bones, liver,lungs or brain. On occasions, melanoma may be flesh-coloured, making its early detection difficult.
The outlook for a melanoma is good if it is found early. To enable early detection of melanoma, anyone with a family history of melanoma and anyone who has multiple moles should be examined regularly by an appropriately trained and experienced doctor (such as a dermatologist).
How do I Prevent Sun Spots or Skin Cancer?
To minimise your chance of getting skin cancer:
- Avoid the sun in the middle of the day (10 am to 3 pm) as much as possible
- Stay in the shade whenever possible
- Wear protective clothing and a hat when outdoors
- Apply SPF 30+, broad-spectrum sunscreen to the skin. Apply sun block
20 minutes or so before going outside and reapply every two hours while
in the sun - Regular skin checks by your GP or dermatologist, especially if new and
persisting skin spots develop.
