What is Skin Cancer?
Skin cancers are malignant tumours that arise from cells found in the skin tissue. They arise due to the development of abnormal cells from the epidermis, and which have the ability to spread o other parts of the body. There are different types of cells in the skin tissue and abnormal growths of these cells can give rise to different types of skin cancers. There are three main types of skin cancers, which are broad into two groups – non-melanoma skin cancers (NMSC) which consist of basal-cell skin cancers (BCC) and squamous-cell skin cancers (SCC) that are more common, and melanomas, which are less common but more aggressive skin cancers.
What are the types and symptoms of Skin Cancer?
BASAL-CELL SKIN CANCER
Basal-cell skin cancer (BCC), also called basal-cell carcinoma is the most common skin cancer. There are several different types of basal-cell carcinoma, including the superficial type, the nodular type and the morpheaform. This skin cancer usually appears as a painless, raised area of skin that is smooth. Sometimes small blood vessels called telangiectasia can be seen within the tumour and at times crusting and bleeding in the centre develops. The superficial type and nodular type of tumour is treated relatively easily and often without scarring. However, the morpheaform type is more challenging to treat as the tumours can often grow into the surrounding tissue. Basal-cell skin cancer usually forms on sun-exposed areas of the skin.
SQUAMOUS-CELL SKIN CANCER
Squamous-cell skin cancer (SCC), also known as squamous-cell carcinoma usually appears as a red, scaling, thickened patch on sun-exposed skin. These tumours may become ulcerated or bleed. When not treated, it may develop rapidly into a large lump on the skin surface. Squamous-cell carcinoma is the second most common skin cancer and is a more dangerous form of skin cancer than basal-cell carcinoma as it is more likely to spread to other areas of the skin. However, it is not as dangerous as melanoma.
Most melanomas consist of various colours from shades of brown to black, although there are some melanomas that appear pink or red. Melanomas with this appearance tend to be more aggressive and are referred to as amelanotic melanoma. Melanomas tend to appear as irregularly shaped moles with an irregular border and colour variation within the mole. Malignant melanomas tend to change in size, shape, colour or elevation. Some other signs of malignant melanoma include pain, itchiness and bleeding on or around the mole and the sudden appearance of a new irregularly shaped mole in adulthood.
To help identify malignant melanoma, you can employ the “ABCDE” method of differentiation – A stands for “asymmetrical”, referring to the asymmetrical shape of the mole (draw an imaginary line through the centre of the mole, and if one side appears different from the other, you should visit a skincare specialist; B stands for “borders” referring to the irregularity of the mole borders; C stands for “colour”, of which malignant melanomas tend to have different colouring within the mole itself; D for “diameter” larger than 6mm; E for “evolving.”, referring to the mole changing shape, colour or bleeding suddenly.
What are the causes of Skin Cancer?
The primary environmental cause of skin cancer is sun exposure. Other causes include smoking, exposure to radiation such as x-rays and artificial UV rays (through overuse of tanning beds for instance), and the use of immunosuppressive medication such as cyclosporin A and azathioprine. There are also some genetic factors that contribute to the risk of getting skin cancer, including congenital melanocytic nevi syndrome which results in the formation of nevi from birth and pose the risk of becoming cancerous.
What are the common types of Skin Cancer in Singapore?
Based on statistics from the Singapore Cancer Registry (Trends in Cancer Incidence in Singapore 2010-2014), there are 1,719 and 1,381 cases of skin cancer in Singaporean men and women every year, respectively.
The most common skin cancer in Singapore is basal-cell carcinoma, which is typically located on sun-exposed areas such as the head and neck region although they can also occur on covered areas such as the back. This prevalence is probably due to our location in the tropics and the habits of many Singaporeans to wear clothing that exposes more of their skin due to the high temperatures experienced here during the day.
Is there a cure for it and what are the treatment types?
Most skin cancer types can be cured by excision of the lesion with an adequate clear margin. Depending on the location and size of the lesion, more complex surgical procedures involving skin grafts may be needed sometimes. Certain types of skin cancers can also be treated using cryotherapy (freezing with liquid nitrogen), curettage and electrosurgery, photodynamic therapy (which uses light and a photosensitising agent to kill cancer cells) and radiation therapy.
How do I prevent Skin Cancer?
Use adequate sun protection as ultraviolet radiation from the sun is the most important risk factor. Sunscreen, the use of hats and umbrellas and appropriate clothing for outdoor activities are essential. Skin self-examination and awareness can also aid in the early detection of skin cancers. People with badly sun-damaged skin should see a dermatologist for skin checks as some pre-cancerous lesions can be treated as a preventive measure. Pay particular attention to irregularly shaped moles and moles that appear suddenly in adulthood, or those that bleed or change their shape over time.
Get a broad spectrum sunscreen that protects against UVA and UVB. The SPF (sun protection factor) is a measure of its ability to protect against UVB. I recommend something with an SPF of 30 or above. Protection against UVA is provided by ingredients such as avobenzone, oxybenzone, ecamsule, titanium dioxide, and zinc oxide, so look out for these.