Skin Cancer Screening

What is skin cancer?

Skin cancers are malignant tumours that arise from skin tissue cells. They arise due to the growth of abnormal cells from the epidermis. These abnormal cells can have the ability to spread to 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.

What are the types of skin cancer?

There are three main types of skin cancers:

1. Non-melanoma skin cancers (NMSC) which consist of basal-cell skin cancers (BCC)
2. Squamous-cell skin cancers (SCC) that are more common
3. Melanomas, which are less common but more aggressive skin cancers.

What are the symptoms of skin cancer?

Basal-cell skin cancer

Basal-cell skin cancer (BCC), also called basal-cell carcinoma is the most common skin cancer. BCCs usually appear as a painless, raised area of skin that is smooth. Sometimes small blood vessels called telangiectasia can be seen within the tumour and the center might develop crusting and bleeding.

There are several different types of basal-cell carcinoma, the 3 main types are:

1. Superficial: Appears as a flat, reddish patch, typically on the upper torsi and shoulders. Easy to treat and often leaves minimal scarring.
2. Nodular: Appears as a small, round, shiny raised bump. Easy to treat and often leaves minimal scarring. Most common form of BCC.
3. Morpheaform: Appears as a white, scar-like area. More challenging to treat as the tumours can grow deeper 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 into a large lump on the skin surface. Squamous-cell carcinoma is the second most common skin cancer and is a more dangerous than BCCs as it is more likely to spread to other areas of the skin. However, it is not as dangerous as melanoma.

Melanoma

Most melanomas consist of various colours from shades of brown to black, to even pink or red. Pink and red Melanomas 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 border
• 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. Genetic factors can also contribute to the risk of getting skin cancer, including congenital melanocytic nevi syndrome which results in the formation of nevi from birth that poses 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), about 1,719 men and 1,381 women are diagnosed with skin cancer each year.

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 skin cancer and what are the treatment types?

Most skin cancer types can be cured by excision of the lesion with an adequate and 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 to prevent skin cancer?

1. 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.
2. Skin self-examination and awareness can also aid in the early detection of skin cancers.
3. 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.
4. Pay particular attention to irregularly shaped moles and moles that appear suddenly in adulthood, or those that bleed or change their shape over time.
5. 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.