Thursday, January 26, 2012

Too much sun? The dangers of sun exposure faced by sea kayakers.

The following article first appeared in issue 29 of Ocean Paddler magazine, which was published in December 2011. Since it was published I have developed a possible third recurrence of skin cancer and it was surgically removed earlier this week. I now await the pathology report to see if any further surgery might be required. I have decided to publish the article in full here. By coincidence Silbs also posted a recent note on sunscreen. Be warned! 

Photo by Donald Wilcox. Dressed for the Scottish summer. Broad brimmed hat, sun glasses, wearing factor 30 and note sun protection bottle on back deck beside splits!

A personal story of skin cancer.
I guess I should have known better. My father had fair hair and skin and after a lifetime of sailing he developed a basal cell carcinoma  (a type of skin cancer caused by sun exposure) on his cheek. He ignored it too long and by the time he went to see about it, the ulcer had spread throughout his skin and nearly half of his face had to be removed and replaced by a graft of skin from his shoulder and back. This had to be moved up to his face leaving a tube of skin going down to his shoulder until the graft successfully took.

After this I was a bit more careful in the sun but since I am dark haired (at least I was) and took a good tan I didn't think I had much to worry about. By careful, I mean I started wearing a broad brimmed hat in the sun but there are not that many sunny days in the west of Scotland. However, I had underestimated the cumulative effects of spending long hours outdoors. Even on cloudy days the sun's rays can still do damage. Since childhood I have spent most of my weekends outdoors, sailing, windsurfing, hill walking, mountaineering, mountain biking and since 2002 sea kayaking.

About 2005 I was aware that I had developed a small pigmented "mole" on my right cheek. It was just slightly darker than my skin and it was smooth, I couldn't feel it. Its border with my normal skin was also very even, it was not a ragged mixture of my normal skin and pigmented skin. It did not hurt and it wasn't itchy and it didn't bleed or develop a crust. It was growing only very slowly and was only about 4mm in diameter so I didn't think I had anything to worry about  but I did start using  factor 30 sun screen even in winter.

Then in 2009 I noticed it had grown to about 8mm with a little darker lump in the middle, a bit bigger than a pin head. I went to my GP. He looked at it with a magnifying glass and referred me to a dermatologist. I didn't have long to wait and I soon saw the consultant. She asked me how long I had had it. She asked if I had a family history of skin cancer and I told her about my father. She then asked if I had ever been sunburned as a child (I had), whether I ever sun bathed or used sun beds ( I didn't). Next she asked if I had an indoor or outdoor job (I work indoors) and if I had any outdoor hobbies (I had to own up and plead very guilty at this point). The consultant then examined my mole with a very bright light and binocular magnifying lenses. She also examined my back, front arms and legs and asked if my 4 other moles had changed at all. I told her that I had had those ones from childhood and that they had not changed.

She told me that she thought I had an early form of skin cancer. The mole looked like something called lentigo maligna and the dark lump might be a melanoma in situ. Yikes, I'm not a dermatologist but I know that a melanoma can be a really serious form of cancer. She reassured me that it was at an early stage and unlikely to have spread out of the top layer of skin (in situ) but it would need to be removed. I started to put my jacket on. She said it might be better not to get dressed just yet as they would take me through to the operating theatre next door, right now!

I lay there under an operating light that seemed brighter than the sun. Tissue paper was laid over me covering everything but my right cheek. I hardly felt the local anaesthetic being injected and was aware only of a tugging sensation as the dermatologist cut the mole away then sewed my skin together. She told me that she had removed it completely and put 4 small stitches in. She said the mole would be sent to pathology where they would examine it with a microscope and make sure there was a safe border of healthy skin all round the mole. I was given a letter to take to my GP to get the stitches out and the consultant said that should hopefully be the end of it.

A few weeks later I was quite pleased with the result, you could hardly see the scar except for a little brown bump that came out of the middle of the scar. I was half wondering whether to go and see about this when I got a phone call, "Could you come back to the Dermatology clinic? Today please." Two hours later I was back in the operating theatre. The consultant told me that her suspicion had been correct. I did have a melanoma, it was still likely to be "in situ" but the biopsy had abnormal cells right up to one edge.  She said she would now take a wider excision. If this one had normal cells all round the edge then I would most likely not need further treatment. If there was still abnormal cells to the edge of the biopsy then I would need further treatment, which could include chemotherapy. I  came out in a cold sweat under the tissue paper and the hot lights.

This time the excision was bigger and I had 8 small stitches.  Fortunately for me, pathology confirmed that all of the melanoma had been excised this time. All I am left with now is a slight puckering of the skin on my cheek though I still have annual checkups. Luckily my skin cancer was detected at an early stage and the treatment has apparently completely removed it. Not everyone is so lucky. Bob Marley, the Jamaican musician, died from a malignant form of melanoma. Although he had dark skin  (and skin cancer is less common in dark skinned people) he had inherited a genetic susceptibility from his white father.

How common is skin cancer?
First of all, skin cancer is subdivided into two main types, depending on what skin cell type the cancer grows from. The two divisions are:  1. malignant melanoma (from melanocyctes or pigment cells) and 2. non melanoma skin cancer (from basal cells and  squamous cells). Melanocytes are the cells that form moles and freckles and also allow you to tan. Table 1. shows the number of new cases and number of deaths of both types of skin cancer in Scotland in 1985 and 2009.

Table 1. Skin cancer in Scotland (population approximately 5 million).

New cases
New cases

Malignant melanoma
Non melanoma skin cancer
Data extracted from the Scottish Cancer Registry (new cases) and the National Records of Scotland (deaths)

The first thing to note is that the number of new cases of skin cancer has approximately tripled between 1985 and 2009. This is thought to be mainly due to increased exposure to the sun and increased use of tanning beds over that period. Next, although non melanoma skin cancer is commoner, it causes fewer deaths than malignant melanoma. This is due to a number of reasons, melanoma is both more likely to spread to other parts of the body and it is more difficult to treat.

So what can we do to reduce our chance of developing skin cancer?
To answer this we need to understand the risk factors that contribute to developing skin cancer. Some of these are non avoidable and some are avoidable and are listed in Table 2.

Table 2. Risks for skin cancer
Non avoidable risks
Avoidable risks
        family history of skin cancer
         multiple moles
         unusual mole(s)
         fair skin
          red or blonde hair
          blue or green eyes
        age over about 50y          
     also having some other rare skin disorders
        any treatment that might suppress the immune system e.g. treatment for another cancer or following an organ transplant
         number of blistering sunburns under age 20y
         total time exposed to sun
         number of intermittent exposures to strong sun
         indoor occupation/outdoor recreation
         tanning bed sessions

If you have any of the unavoidable risk factors in Table 2, then you need to be even more careful to take note of the avoidable risks. If you are over the age of 20y then previous sunburns will now be an unavoidable risk but take particular care of the youngsters in your family. We obviously can't avoid exposure in our chosen outdoor recreation of sea kayaking, so we literally need to undertake some serious damage limitation. It goes without saying that unless we are deep inside a cave, sea kayakers spend much of the day out of the shade. We don't just get blasted by the sun's rays from above, reflections from the water hit us at all angles.

The sun is at its strongest between the hours of about 10am till 3pm when  it is high in the sky. It is also stronger in the tropics, though in northern latitudes in summer, it makes up for being lower by shining longer.  The midsummer sun is above the horizon for 17.5 hours a day in sunny Glasgow. The most damaging parts of the sun's radiation spectrum that penetrate the atmosphere are the UV rays, especially UVA. The majority of these will still reach sea level even when it is overcast. UVA can penetrate deep inside the skin cells and damage and mutate their DNA, which is necessary for the cells' normal function and division. Melanocyte cells produce the pigmented protein melanin, which helps block the UVA rays from penetrating the skin especially in dark skinned people (but remember Bob Marley.) Sun protection products are designed to work like melanin and block the UV radiation from penetrating skin. The higher the protection factor, the better and this is especially of benefit to light skinned people.

A broad brimmed hat will give a head start as melanomas can occur on the scalp of even dark haired and skinned people. In the UK we will often be wearing a cag when sea kayaking (even when it's sunny) but that still leaves the hands, face, lips, neck and ears exposed. Several applications of factor 30 water resistant sun protection should be applied throughout the day. I particularly like Ambre Solaire transparent protection spray. It is factor 30, non greasy and water resistant. It doesn't affect grip on the paddle and doesn't seem to sting the eyes as much as some products. If you wear a hat, you can avoid putting protection on your forehead, then when you sweat, it won't carry the product down into your eyes. When wearing a short sleeved top in warmer weather, remember to cover exposed areas of the arms and neck with sun protection. Check that the material of the top also offers sun protection, not all do. Remember to keep covered up when you stop for lunch as this is when the sun will be at its highest and UVA radiation is strongest. If you take your cag off, be sure to apply sun protection to any exposed skin. I keep the bottle handy under the short loop of deck elastics, which are designed to retain paddle shafts. The Ambre Solaire bottle has some useful indentations in which the elastic can sit. Fair skinned people from northern latitudes who sea kayak in the tropics (where UVA rays are strongest) may require additional measures  such as gloves to protect the backs of the hand and UV face buffs or complete sun block cream for sensitive areas such as the lips or the bridge of the nose. Sun block is usually zinc based and may be opaque white or sometimes can be found in garish fluorescent colours.

Finally it is important to let a little sun light reach your skin now and then as the skin is only able to make vitamin D in the presence of sunlight. Dark skinned people in northern latitudes need to be especially careful about this. However, a "little sun" does not mean several hours of unprotected exposure at mid-day.

How to spot something that might be early skin cancer.
Skin cancer takes a long time to develop and in the early stages, early cancer will appear as a small slow growing lesion on the skin, which may or may not be pigmented. Most people commonly describe any small lesion as a "mole". So how do you know if a "mole" needs to be seen by a doctor? Basically any mole that is changing needs to be assessed by a doctor. 

There is also an ABCDE rule that can help you decide whether a mole should be seen by a doctor.
A. Asymmetry: normal moles or freckles are symmetrical.  Seek advice if a mole has an irregular shape.
B. Border: a normal mole has an even border with the surrounding normal skin. Seek advice about a mole with an irregular border.
C. Colour: a normal mole has an even colour. Seek advice about a mole with two or more colours.
D. Diameter: a normal mole is usually less than 6mm in diameter, seek advice about a bigger mole.
E.  Elevation: normal moles are usually flat, seek advice if a mole is raised above the skin, particularly if it is getting higher.

In addition to the things in the ABCDE rule, any mole that becomes itchy, painful, scaly,  forms an ulcer or oozes fluid or blood needs to be seen by a doctor. If you become concerned, the first person to see is your GP. He or she will examine it and then decide whether to refer you to a dermatology consultant at a hospital outpatient department.

UV rays do not just damage skin, they also damage the clear lens of the eye causing the development of cataracts in later life. Clouding of the lens caused by cataracts can seriously affect vision and you may need an operation to remove the damaged lens to restore vision.  Although cataracts take many years to develop, it is worthwhile taking  preventative measures while you are young because, like skin cancer, the risk of cataracts is increased by the total time exposed to the sun. You should consider wearing sunglasses while sea kayaking, even on cloudy days and in winter.  Don't just buy sunglasses because they look good, check the label and ensure they block at least 95 percent of UVA  and 99 percent of UVB rays. If they don't, they might be worse than useless as they can cause the pupil to dilate letting in even more UV rays than if you were not wearing them at all.

In Conclusion.
Don't be complacent about the sun just because it feels nice. A sea kayaker's lifetime exposure to the sun will be very considerable. So reduce your exposure, wear a broad brimmed hat, regularly apply factor 30 sun protection to any exposed skin and wear good quality sunglasses, even when it is cloudy  or in the winter.

Of course too much sun does not just cause skin cancer and cataracts. If you want your skin to look like a prune:  old, wrinkly and brown, stay out in the sun!