Be good to your skin, it’s the first line of defence
Skin cancer causes almost 160 deaths a year in Ireland, and can be much more difficult to treat than other cancers, so why do so many of us take risks with it?
Skin is the largest organ of the body, and makes up about 15 per cent of our body weight. Photograph: Getty Images
It is exquisitely tailored, smooth and beautifully finished yet hard-wearing, fully water-proof and breathable. It also has all the extras you might want, from UV protection to temperature control.
No this isn’t a miracle fabric or the latest in fashion. We are talking about skin. It is remarkable stuff, the largest organ of the body. It makes up about 15 per cent of our body weight and if spread out would cover 1½-2sq m.
Most of us don’t recognise skin as a key organ. Mostly we just ignore it, but we also put it at risk by overexposing it to the sun. However, if you treat it right it will last a lifetime.
“It is a vital organ in terms of being a package that holds the body together and also in terms of defence,” says Prof Bryan Hennessy, professor of medical oncology at the Royal College of Surgeons in Ireland. “People talk about the immune system but they forget skin is the first layer of the defence system.”
This time of year we benefit from skin’s ability to regulate our temperature on warm days, producing perspiration that evaporates to help us shed unwanted heat.
There is another protective function that has implications for our very lives. “Protective factors help prevent the skin from being damaged by ultra-violet light exposure from the sun,” says Prof Jochen Prehn, professor of physiology at the Royal College of Surgeons in Ireland and director of its centre for systems medicine. Both he and Hennessy are part-funded by the Irish Cancer Society.
UV radiation easily penetrates the epidermis or outer surface of the skin to reach the inner layers or dermis. These layers hold nerve endings; sweat glands; hair follicles; and skin pigment cells called melanocytes, which release melanin, the substance that makes you tan and protects your skin by absorbing UV.
However, when we are careless with the sun and repeatedly receive too much UV, we can get more than sunburned skin. DNA in the melanocytes can be damaged to trigger skin cancer – melanoma – which causes almost 160 deaths a year in Ireland, according to the National Cancer Registry.
And it can be UV from any source. Irish people are “literally risking their lives” when they use sunbeds, the Department of Health said in a statement last week. The Government ban on use of sunbeds for those under 18 came into force this month.
“A lot of what is going on is still not understood but UV is known to be damaging to DNA and so excessive exposure does result in changes that can transform into cancer cells,” says Hennessy.
Melanoma presents a significant risk, because it tends to spread cancer to other tissues, making treatment much more difficult. Research is under way to find better ways to treat this difficult disease.
Hennessy worked with Prof William Gallagher, professor of cancer biology at University College Dublin and other colleagues including Dr Máirín Rafferty at UCD. “We were trying to find proteins or other factors that drive the disease and also find markers that could predict how aggressive the disease will be,” says Rafferty. “Being able to predict overall survival has an impact on treatment. If you know it is a more aggressive form, then the treatment will be aggressive.”