Skin cancers: be aware of the dangers

Because frequent and prolonged exposure to ultraviolet (UV) radiation from the sun is mainly responsible for these cancers, westerners from temperate climates living in tropical countries are at higher risk than their fellow citizens back home. Like other cancers, awareness and early detection are key to a successful outcome. 

Skin cancer is an anarchic growth of skin cells found in the epidermis, the outer skin layer. There are two main types of skin cancers: the non-melanoma types, which are often not too serious and account for about 90 per cent of skin tumours and melanoma, the severe type that is much less frequent but is responsible for most skin cancer deaths. 

Affecting both genders around 50 to 60 years of age but more frequent in men, non-melanomas include squamous cell carcinoma, which originates from the squamous cells of the outer layer of the skin and the more common basal cell carcinoma that grows in the basal cells beneath. 

From the initial lesion, which appears usually on sun-exposed areas such as the face, ears, neck and hands, most skin carcinomas slowly progress and rarely disseminate within the body.

The carcinoma lesions appear as flat spots with a crusty surface, small reddish nodules or pearly bumps or sores that do not spontaneously healed.

Melanoma can affect both old and young people including teenagers and originates from the cells known as melanocytes, which lie in the deeper layer of the epidermis. The cells produce the melanine pigment that is responsible for the protection of the skin from ultraviolet radiation. In men, melanoma typically happens on the face and trunk and in women on the trunk and legs. It can arise on a pre-existing mole (in 30 per cent of the cases) or as a new lesion beginning on normal skin. Its overall appearance tends to rapidly evolve, with the colour changing from light brown to black, blue black or red, its edges going from well-curved to ill-defined contours and its thickness from flat to thickened irregular lesions with possible spontaneous bleeding. The core issue for melanoma is its ability to quickly produce secondary tumours, known as metastasis, which can lead to life-threatening complications affecting the liver, brain, lungs and bones.

The risk factors for any skin cancer include fair complexion (white skin, blond hair and light-coloured eyes), skin with lots of nevus (moles) or that is prone to sunburn, cumulative exposure to intense UV radiation, in particular severe sunburn in childhood, prolonged exposure related to certain occupations (fishermen, farmers) or recreational activities (water sports, skiing, jogging), the use of tanning beds, a family or personal history of skin cancers and a weakened immune system. 

Contrary to popular belief, a supposedly healthy tan provides no protection against sunburn but is the result of an actual skin injury due to excessive and/or too intense UV radiation. 

Melanoma can affect all skin tones and occur on any areas of the body, exposed or not to the sunlight including mucosa such as in the mouth, nose, throat, the vagina or the anus. 

If you notice some suspicious changes on an existing mole or the appearance of a suspect lesion for a few weeks, it is wise to see a dermatologist without delay. Following a thorough skin exam, the doctor may suggest a biopsy – the partial or total removal of the lesion for microscopic analysis. When diagnosed early, skin cancer is cured by the surgical excision of the tumour. However, if the cancer (especially melanoma) has already spread into lymphatic nodes or other organs, a complete evaluation of the disease extension – known as staging – is required to determine the most appropriate therapeutic option. This can involve surgery, radiotherapy and chemotherapy. 

Prevention and early detection are fortunately effective. Even though moderate sun exposure is beneficial for the optimal synthesis of the bone-strengthening vitamin D, it is essential to adopt preventive measures to limit the sun’s deleterious effects on the skin. These include:

- Avoiding the most intense periods of sunlight from 10am to 5pm;

- Restricting the sun exposure based on your personal risk and intensity of current UV levels;

- Covering your body with appropriate clothing and hat;

- Correctly and frequently applying broad spectrum (UV A and UV B) sunscreen of at least 30 SPF;

- Protecting your eyes with adequate sun glasses; and 

- Refraining from using tanning booths. 

More stringent precautions should be taken for children. 

Early detection is based on regular self-examination. In addition, an annual full skin and mucosa check by a dermatologist is highly recommended especially for at-risk individuals living in tropical countries. 

 

Dr Gerard Lalande is managing director of CEO-Health, which provides medical referrals for expatriates and customised executive medical check-ups in Thailand. He can be contacted at [email protected],