SKIN CANCER: COULD IT BE ME?
LET’S FACE FACTS
Did you know that Skin cancer is more common than all other cancers combined? While on average of 120 per 100 000 Americans or Europeans get newly diagnosed with a non melanoma skin cancer every year it is a 50 - 100 times more common when we look at African figures. Skin cancer is caused by the sun, in particular by exposure of the skin to UV-radiation. Southern Africa has one of the highest monitored levels of Ultraviolet radiation, only equalled by Australia, New Zealand and some parts of South America. Now why is that so? The African-especially Sub Sahara continent has naturally got a higher UV-concentration because where the sun is standing almost vertical over the equator the time for absorption of harmful radiation is shorter. It is the function of the ozone in the stratosphere to absorb the high energy UV-rays and a 10% depletion in ozone leads to a 20% increase of UV radiation and a 40% increases in Skin cancer!
BUT WHAT EXACTLY IS SKIN CANCER?
There are three types of skin cancer: The so-called Non-melanoma skin cancers:
Basal cell carcinoma and Squamous cell carcinoma and the Malignant Melanoma. What do those cancers look like?
Maybe one should look at the skin first to understand what is happening.
STRUCTURE AND FUNCTION OF THE SKIN
The skin is a multi-layered structure covering the whole body and it is actually the body's largest organ. It consists of three layers: the epidermis (outer layer), the dermis- the thick part one feels when one lifts up the skin and the subcutaneous tissue, which is the fatty cushion the skin rests on.
The epidermis consists of the basal layer, from which regeneration takes place, the squamous layer which makes the bulk of the epidermis and the horny layer which are the dead cells on the outside. In between those layers lie Melanocytes, which are pigment-producing cells. The dermis contains the structural fibres (collagen and elastin), blood vessels, sweat and oil glands and hair. One problem for the skin is that it is inevitably exposed to environmental insult from sun, heat, cold, mechanical and chemical factors. UV-damage and skin cancer happens mainly in the Epidermis but skin ageing involves the dermis.
The first visible change would be a red spot, then comes a scale or scab, which in the beginning comes and goes, which is all that we find in a "Solar Keratosis" or sunspot, which is not quite cancer yet. Later there will be sores or scabs which just don't heal and that is already skin cancer. Not all skin cancer will or can kill you but if left untreated it grows relentlessly and it may cause major cosmetic problems (taking into account that skin cancer very commonly involves the face). As mentioned we have 2 different types of skin cancers, the Basal cell carcinoma (BCC) and the Squamous cell carcinoma (SCC). The former grows very slowly and eventually forms an ulcer that never heals. It is locally destructive, but cannot spread into the blood or lymph system. BCC's most commonly occur on the face or trunk. SCC's grow more aggressively, more tumour like (exophytic), involve the extremities or face and can (although rarely) invade your lymph or bloodstream and therefore affect other organs. However there is of course also the malignant melanoma. This either starts with a mole which is changing or just a new black spot. What might look like a freckle today could be a killer tomorrow. Treated early the prognosis is still excellent-left too late it can spread to all vital organs and ultimately cause death. In addition to that, while other skin cancer usually starts in the 5th decade of life melanomas occur in the young, often between the ages of 20-30. And to make matters worse: while the incidence was 1: 1 000 some 40 years ago it is 1 in 75 in Africa and Australia today which probably means that all of us will know somebody who will die of malignant Melanoma.
SO HOW DOES THE SUN CAUSE CANCER?
The major environmental facts that can cause serious damage to our skin is ultraviolet light. It has been fashionable to acquire a tan for the last 50 to 60 years. This together with profound changes in the protective ozone layer has put an unmanageable burden on our skin. The spectrum of UV light emitted from the sun can be divided into UVA, UVB and UVC.
The shorter the wavelength the higher the energy and the more potentially harmful! UVA has a long wavelength (320 - 400nm), a relatively low energy and therefore penetrates deep into the skin. At that depth we find all the elastic fibres, which get selectively destroyed by the UVA energy. What does that mean? Ageing and wrinkling!!! But we also know now that UVA greatly contributes to the skin's susceptibility to UVB damage.
UVB has a much higher energy (290 - 320nm), and when enough of it gets absorbed by the skin, it can change the genetic information of the cell and turn it into an abnormal or cancer cell.
And then there is UVC (270 - 290nm). UVC has the highest energy, in fact so high that it used to get fully absorbed by the ozone layer of the atmosphere. With the formation of the ozone hole some ten years ago UVC was registered on the surface of the eartH for the first time. UVC is so strong that it causes a blistering sunburn in the unprotected skin; as little as three contacts over a lifetime can cause skin cancer! Presently the southern hemisphere in particular Southern Africa (as well as Australia and New Zealand) suffer the full effects of the ozone hole during the entire summer months where we spend a lot of time outdoors.
So how can a normal cell turn into a cancer cell?
Every cell carries its genetic information well protected inside its own nucleus. The DNA regulates all major functions like metabolism, cell-growth and repair as well as reproduction. We do know now that the energy of UV radiation leads to production of radicals, which in turn can crack the genetic coding and cause DNA mutation. This can lead to uninhibited growth and reproduction, which per definition is the basis of any cancer. And we have to understand the skin unfortunately never forgets or forgives ... any overdose of UV contact as seen in sunburn, causes damage which accumulates over the years. In-fact most of the damage to the skin occurs in the first 20 years of our lives. 80% of the total lifetime UV exposure is acquired in childhood with time more and more cells escape the control of the immune system and that's why skin cancer only manifests itself later in life.
Now that is quite scary - but of course this is only the one side of the story! It can't and doesn't mean from now on we all have to live indoors or else pack our bags and live somewhere in the Highlands of Scotland where the sunshine is a rare phenomena. Far from it!!! Education is the first step towards prevention and this is where the secret lies: There are new rules, which we need to follow to adapt to our changing environment.
Taking care of your skin is to take care of your health!
SUNSENSE IS NO NONSENSE!
So what is sun sense?
- Avoid the hours of the day with maximum UV-concentration:
If your shadow is shorter than you: Stay out the sun!
If your shadow is longer than you: You can go into the sun with protection
- Wear protective clothing:
Hats, shirts and pants made from natural fibres (which give much better protection than polyester I nylon) and sunglasses!
(Did you know that sun exposure causes cataracts, which is the main cause of blindness in elderly people in Africa? UV radiation damages the lens in the eye the same way it destroys the skin).
- Protect yourself all year round but especially in all months with an "r" (like December, January etc). Remember while UVB concentration is higher in summer and has a midday peak, UVA radiation is more or less constant throughout summer and winter and during the day.
- And what about sunscreens?
Sunscreens are labelled with an SPF (Sun Protection factor). And although different skin-types can be more or less susceptible to the sun skin cancer can involve all race groups and is more a matter of the time spent outdoors than of the skin-type alone. The "Safe Sun Time" which is the amount of time that you can spend outdoors unprotected without damaging the skin in Southern Africa in the middle of summer is 10 minutes!
It has been shown that regular sunscreen use in children can decrease the cancer risk by 80%. So:
Protect yourself throughout the year. The higher the factor sunscreen the better (but minimum SPF 30) Make sure you never burn!
So what is the right sunscreen?
Well obviously there is no "sunscreen for all" If you run you need a different sunscreen than if you swim, if you have hair chances are you prefer a spray to a cream, and somebody being outdoors the whole day will use a different sunscreen than someone who is outside only for half an hour.
The basic principle is: the higher the factor the better. Anything above a factor 30 is fairly safe. (Johnson & Johnson moisturising sun lotion, Piz Buin, Nivea, Dermasure).
Take one point into account when you buy a sunscreen. The ideal sunscreen should have both UVA and UVB screens and this should ideally be indicated on the bottle. Take for instance Vichy extreme sunblock milk: it is a SP 60 (which is the UVB screen) and UVA Index of 16 (the highest UVA Index is 20). It is an oil-free base and brilliant to use as a daily sunscreen as the chemicals used are safe, and it gives long-lasting protection and is cosmetically acceptable.
So what is the message? Yes our environment has changed and all of us have probably got quite a high chance to get one or other form of skin cancer. But what can we do about that? Firstly we must change our attitude and make sure you never burn. After all prevention is better than cure!
Secondly: if any "spots" come up, go for a skin check. Everybody should probably have a check-up every 1-2 year's after the age of 30-35.
And finally: if you have got a lot of moles have your risk properly assessed. Early detection of a malignant melanoma is of the utmost importance. To find out whether your moles are dangerous or not takes a Dermatologist one look and one dermatoscopic examination. It is definitely not necessary to remove all moles. Even irregular or abnormal moles - and some people have got hundreds of them - can nowadays be "mapped", which means they get stored to be compared as a follow up visit. That way we can pick up changes as small as 1 mm.
Well - the environment changes but so does our technology! We have got fantastic sunscreens to protect our skin, we have got sophisticated diagnostic tools to help recognise skin cancer early and early skin cancer is very treatable - so we don't have to move to those dark and cold climatic zones quite yet! But what we do need is knowledge and education to create the necessary awareness to be able to prevent the detrimental effect of the increased UV radiation on the human skin.
SKIN CANCER CAN HAPPEN TO ANYONE SO BE SMART: PROTECT YOURSELF
The above article was compiled by Dr. Dagmar Whitaker – www.capetowndermatologists.co.za