Two types of non-melanoma skin cancer are common: basal cell carcinoma (BCC) and
squamous cell carcinoma (SCC). Both are seldom a threat to life. If removed at an
early stage and with good medical care, the mortality rate is less than 1%. Nevertheless,
they can severely damage the skin. Because both occur mostly on the visible sun-exposed
body parts, in particular the head and neck, the cancers can disfigure a person’s
appearance.
Less common but more dangerous is malignant melanoma. It usually develops on sun-exposed
body parts but can appear in different forms anywhere on the body, even in the eye.
Unfortunately, it very often looks like a benign mole somewhere on the skin (see
‘Non-cancerous growth’). The cancer readily spreads via lymph and blood vessels to
other body tissue or organs. In almost a quarter of melanoma cases, the survival
rate is low.
Both cancer types, non-melanoma and melanoma, can arise from sun damage. UV radiation
scrambles the chemical code of skin cells – the DNA. The skin’s repair system can
no longer read the code and generates an out-of-control malignant growth. In some
cases, UV radiation is only the trigger and the repair system could have inherited
a genetic fault that prevents it from properly reading the code. Other possible causes
are a suppressed or defective immune systems and certain toxic substances.
Fair-skinned and light-haired people lack the amount of skin pigment, melanin, that
provide a protective shield against UV radiation. Skin cancer is, therefore, much
more prominent in such populations, although not exclusively. Other genetic factors
that are related to an increased risk are a tendency to sunburn instead of tanning,
and a high number of moles.
Today skin cancer is more prevalent than all other human cancers combined. Is the
weather to blame? Yes and no. UV radiation is undoubtedly a major trigger of skin
cancer symptoms. But equal blame goes to a change in contemporary human behavior,
as more leisure time and the desire for a tan lead to more radiation exposure.
Despite education and early detection programmes, numbers of skin cancer patients
are rapidly increasing everywhere. Fortunately, an average of about 95% of diagnoses
is of the less lethal non-melanoma skin cancer type. The sun-soaked Australians hold
the infamous world record for the highest melanoma rate, at 9.6% of total national
cancer cases against just 2.1% in Europe. Numbers of melanoma cases in the US are
halfway between the Australian and European rates.
