Science – Enjoy summer, but take care of your skin

As a teenager growing up in sub-tropical Australia, my lifestyle was dominated by sports activities like surfing, cricket and tennis. It was not considered “cool” back then to wear a hat or cap and solar block-out creams were largely unknown. It was even believed that spreading coconut oil on the skin helped fair-skinned people like me to develop a tanned skin! The consequence? I am recovering this week from surgical excisions of various forms of skin cancers that are the legacy of my earlier unprotected sporting activities. My message this summer, enjoy yourself, but take care of your skin!

As we enter the sunnier months of the year when solar ultraviolet radiation intensities increase, there is one health threat that everyone in NZ needs to consider and that is skin cancer. The most dangerous common type is melanoma. It is even more threatening to human health than the other common forms – squamous cell carcinomas (SCC) or basal cell carcinomas (BCC), which constitute 95 per cent of all skin cancers. Melanoma, the most dangerous form, causes 75 per cent of all skin cancer deaths.

Melanoma cancers consist of abnormal skin pigment cells called melanocytes. Another type of lesion, actinic keratosis, is precancerous. Melanomas exist in a variety of forms some of which are more dangerous than others.

In scientific terms, according to a US National Institutes of Health review, ultra-violet radiation in sunlight is the most prominent and ubiquitous physical carcinogen in our natural environment. There are three types of ultraviolet radiation that differ from each other in terms of their energy (or wavelength): UVA which causes your skin to wrinkle, tan or burn and too much of which causes skin cancer; UVB which can damage the outmost layers of your skin and can cause sunspots, tanning, sunburn and blistering, which can lead to skin cancer; and UVC is absorbed by the Earth’s atmosphere so is not a factor under most circumstances.

How does UV radiation lead to skin cancer? Our bodies need some UV radiation to form Vitamin D, which is important for human survival. Too much UV damages your cells and so also damages the cellular DNA, which causes a loss of cellular function. As a result, the cells divide and replicate too quickly, and the cells clump together and may form tumours, which can be cancerous.

Skin cancers caused by UV radiation usually affect skin that is more exposed to solar radiation, but they can form anywhere on your body. If you are concerned and wish to avoid health problems associated with skin cancer, and especially melanoma, you will need to consult your general practitioner and then probably a medical skin specialist. Above all, if you have any suspicion that you have a skin cancer, consult medical experts immediately. The earlier a melanoma or any skin cancer is detected and treated, the better the prospects are of successful treatment.

Primary information source: my.clevelandclinic.org