Skin Cancer - Types, Causes & Prevention
What is skin cancer?
Skin cancers, or skin neoplasm's, are growths generally found on the epidermis (the outer layer of skin) with different causes and varying degrees of malignancy. As most of these growths, or tumours, occur on the outer layer of skin, they are generally visible. This is turn makes the majority of skin cancers detectable in the early stages of growth.
Australians have one of the highest rates of skin cancers in the world. Over 1850 Australians will die each year from skin cancer, while two in three Australians will be diagnosed with skin cancer by the age of 70 (ABS, 2010).
Types of skin cancer
There are three main types of malignant skin cancers, named from the cells they develop from. They are able to be placed in two specific categories: Non-melanoma skin cancers & malignant melanomas.
Non-melanoma skin cancers include squamous cell carcinomas and basal cell carcinomas. Although rarely lethal, surgical treatment is often painful and can be disfiguring. The rates at which these cancers grow vary from months to several years. The appearances of these cancers do vary:
- Basal cell carcinomas: the majority of these cancers are found on the face and neck, where the skin is exposed to sunlight. They are often mistaken for sores, usually appearing as small, round or flattened spots that are red, pale or pearly in colour.
- Squamous cell carcinomas: under the microscope, these sores seem to have a scaly red appearance, which can bleed and become ulcerous. Like basal cell carcinomas, these cancers are often found on the areas of the skin more often exposed to direct sunlight.
Although non-melanoma cancers are not reported to cancer registries, according to general practice and hospital data, non-melanoma skin cancer is the most commonly diagnosed cancer in Australia. GP consultations to treat non-melanoma skin cancer increased 14% between 1998-2000 and 2005-2007, suggesting a greater need for education regarding these forms of cancer.
Whilst malignant melanomas are far less prevalent than non-melanoma cancers, they are the major cause of death from skin cancer worldwide. However, they are more likely to be detected and accurately diagnosed than non-melanoma cancers. In Australia, figures relating to the incidence rate of these malignant melanomas are staggering, with annual rates 10 and 20 times higher than European rates for females and males respectively.
The growth of melanoma's are rapid, and can develop in normal skin, freckles or moles anywhere on the body, not just in areas exposed to sunlight. In Australia, over 75% of the deaths associated with skin cancer are caused by malignant melanomas.
What causes skin cancer?
Exposure to UV radiation appears to be a major causal factor in the development of all forms of skin cancer. Non-melanoma skin cancers are more prevalent on areas of the body most exposed to sun light, whilst malignant melanoma's, which can develop on areas of the body that aren't exposed to sun light, have been shown to have a positive correlation to high intermittent exposure to solar UV. A number of epidemiological studies supporting a positive association between melanomas and a history of sunburn.
There has also been a large amount of research showing associations between malignant melanomas and an individual's genetic background, with data showing an estimated 10% of melanoma's are in fact familial. This highlights the importance of regular checkups with your GP if you do have a family history of skin cancer.
There are a number of other risk factors associated with skin cancer, and particular care should be taken by those who:
- have a large number of moles on their skin;
- have a fair complexion;
- spend a large amount of time outdoors;
- actively tan using solariums, sun lamps and / or sunbeds.
How can I minimise the risk of skin cancer?
At present, skin cancer is one of the most preventable forms of cancer in the world. Taking basic precautions when you are out in the sun will minimise the risk of UV exposure and skin cancer. These include:
- Using appropriate amounts sunscreen, preferably SPF30+, and re-applying every few hours.
- Wearing sun protective clothing that covers as much skin as possible.
- Seeking shade whenever possible.
- Wearing a hat that adequately covers areas most commonly exposed to sun light.
- Wearing sunglasses that meet the Australian standard AS/NZS1067:2003 for sunglasses.
In Australia, over 95% of skin cancers can be successfully treated if found early. Recently, education programs relating to skin cancer prevention have placed an emphasis on getting to know your skin, so that changes will be picked up quickly. It is important that all Australians, particularly those aged 40 and over, check their skin on a regular basis. If there are any abnormalities, visit your Holdsworth House doctor.