In a report published 10 years ago, skin cancer ranked 10th as the most common cancer in Malaysia, and accounted for 2.6% of all cancer cases in the country.
Unlike other types of cancers, skin cancer has received little attention in Malaysia, and there’s little awareness of it among the public.
The World Health Organisation (WHO) has reported that the incidence of both non-melanoma and melanoma skin cancers has been increasing over the past decades.
Currently, between two and three million non-melanoma skin cancers and 132,000 melanoma skin cancers occur globally each year.
As ozone levels are depleted, the atmosphere loses more and more of its protective filter, which means more solar ultra-violet (UV) radiation reaches the earth’s surface. This increases the risk of developing skin cancer.
Therefore, certain measures have to be taken by the individual to reduce this risk.
Is skin cancer common here?
Skin cancers occur more frequently in people with fair skin. However, they can also affect those with darker complexions.
In Malaysia, the Third National Cancer Registry Report (2003-2005) revealed that skin cancer was the 10th most common cancer in Malaysia, accounting for 2.6% of all cases.
We believe that this figure may be under-reported.
Data from the Dermatology Clinic, Hospital Kuala Lumpur (2006-2014), showed that basal cell carcinoma is the commonest type of skin cancer in Malaysia, accounting for 34.9% of cases. This was followed by cutaneous lymphoma in 25.7% of patients and squamous cell carcinoma in 20.6% of cases.
Melanoma is not very common in Malaysia and occurred in only 5.4% of the patients who attended the Dermatology Clinic in Hospital Kuala Lumpur.
Types of skin cancer
There are two major types of skin cancers:
• Non-melanoma skin cancers, including basal cell carcinoma and squamous cell carcinoma.
• Melanoma, which can be lethal if not detected early.
Other types of skin cancers include:
• Cutaneous lymphoma
• Extra-mammary Paget’s disease
• Merkel cell carcinoma
• Kaposi sarcoma
This article will focus on the two major types of skin cancers, which are non-melanoma and melanoma skin cancers.
Risk factors of skin cancer
You are at higher risk of skin cancer if you have any of these 10 risk factors:
• Fair skin
Skin cancers occur more frequently in people with fair skin.
They have less amounts of melanin (pigment) in the skin, and therefore, get less protection from damaging UV radiation.
• Excessive sun exposure and history of childhood sunburn
Anyone who spends considerable time under the sun may develop skin cancer, especially if they have fair skin, and do not use sunscreen or wear protective clothing.
Outdoor workers such as farmers, gardeners, fishermen and building site workers have an increased risk of non-melanoma skin cancer.
Those who have had one or more blistering sunburns as a child or teenager have an increased risk of developing skin cancer as an adult.
• Multiple moles
People with many or abnormal moles called dysplastic naevi are at increased risk of skin cancer.
• Pre-cancerous skin lesions
Having actinic keratosis increases the risk of developing skin cancer in the future.
These pre-cancerous skin lesions appear as rough, scaly, brownish patches.
They commonly occur on the face, head and hands of fair-skinned people with sun-damaged skin.
• Personal history of skin cancer
If you developed skin cancer in the past, you are at higher risk of developing it again.
• Family history of skin cancer
If you have a positive family history of skin cancer, there is a higher chance of developing skin cancer.
• Genetic disorder
People with certain genetic disorders, like xeroderma pigmentosum, where there is an inability to repair UV-induced DNA damage, are also at risk of developing skin cancer.
• Weak immune system
People living with HIV/AIDS and those taking immunosuppressant drugs after an organ transplant have weakened immune systems, which may put them at a greater risk of developing skin cancer.
• Exposure to radiation
History of exposure to radiation may increase the risk of developing skin cancer, especially basal cell carcinoma.
• Exposure to certain chemicals, especially arsenic exposure
Excessive amounts of arsenic ingestion may predispose some people to skin cancer.
Exposure may be through medicinal, occupational or dietary substances.
Recognising skin cancer
Basal cell carcinoma usually occurs on sun-exposed areas of the skin, such as the head and neck, face, ears and hands.
They may appear as a pearly or waxy nodule, with central erosion and raised border, or a flat, flesh-coloured or pigmented lesion.
Squamous cell carcinoma also occurs on sun-exposed areas.
People with darker skin are more likely to develop squamous cell carcinoma on areas that aren’t often exposed to the sun.
They may appear as as a flat lesion with a scaly, crusted surface, or an ulcerated plaque, or non-healing chronic ulcer.
Melanoma can develop anywhere on the body, in otherwise normal skin or in a pre-existing mole. It is more common in people with lighter skin tone.
In people with darker skin tones, they tend to occur on the palms or soles, or under the nails.
The clinical features suggestive of melanoma can be easily recognised with the mnemonic ABCDE: A – Asymmetrical; B – Borders irregular; C – Colour variegation (two or more colours); D – Diameter larger than 6mm (the size of a pencil rubber); and E – Elevation or evolution of the lesion.
Skin cancer is usually confirmed by a skin biopsy, where a small specimen of the skin is removed and examined under the microscope.
Treating skin cancer
Treatment options for skin cancer depend on the size, type, depth and location of the lesions.
Treatment options available include:
1. Cryotherapy
This can be used to treat some small and superficial skin cancers, and pre-malignant skin cancer (actinic keratosis).
It involves freezing the lesions using liquid nitrogen.
2. Curettage and electrosurgery
The cancer cells are scraped using a curette (circular blade), and any remaining cancer cells at the base are destroyed using an electric probe.
3. Excisional surgery
The doctor cuts out the cancerous tissue and the surrounding margin of healthy skin.
A wide excision, where a larger margin of normal skin surrounding the cancer is removed, may be recommended in some cases.
4. Mohs surgery
This procedure is often used in areas where it’s necessary to conserve as much skin as possible, such as on the face and nose area, or for larger, recurring or difficult-to-treat skin cancers.
During Mohs surgery, the doctor removes the skin cancer layer by layer, examining each layer under the microscope, until no abnormal cells are seen.
This procedure allows the cancer cells to be removed without taking an excessive amount of surrounding healthy skin.
This method is, however, not commonly available in Malaysia.
5. Radiotherapy
Radiotherapy uses high-powered energy beams to kill cancer cells.
This may be an option when cancer can’t be completely removed during surgery, or in patients who are unfit to go for surgery.
6. Topical 5-fluorouracil cream
This is topical chemotherapy, which may be used to treat pre-malignant skin cancers, such actinic keratosis.
7. Topical immunomodulator (5% Imiquimod)
This can also be used to treat actinic keratosis and superficial basal cell carcinoma.
8. Photodynamic therapy
This treatment destroys skin cancer cells with a combination of laser and a cream (aminolavulenic acid) that makes cancer cells sensitive to light.
However, this method is not commonly available in Malaysia.
You can reduce your chances of getting skin cancer by practising these precautionary measures:
• Avoid excessive sun exposure
• Liberal use of sunscreen (SPF more than 30)
• Use protective clothing
• Check your skin regularly and report any change to your doctor
If you have any skin lesions with features suggestive of skin cancer, make an appointment to see a dermatologist.
Not all skin changes are caused by skin cancer. Your doctor will do further investigations to ascertain the diagnosis.
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