Tis the season for excessive sun exposure and excessive sun exposure = risk for skin cancer. Yes, that’s right, that sun exposure that gives you your sexy tan is also the #1 preventable risk factor for all three of the main types of skin cancer. Dermatologists (doctors who specialize in the skin) uniformly recommend protecting your skin when you are outdoors with a sunblock of at least SPF 30 and hopefully that is old news to you, especially if you are a parent, because sunburns when you are young (i.e. in your kids) are an even greater risk factor for skin cancer than they are once you are a crusty old bastard like me. Another good tip is to wear dark clothing and a good broad-brimmed hat when you’re outside and to limit your sun exposure between the hours of 10:00am and 4:00pm, which is the time of day that the sun is most directly overhead in the temperate latitudes (like the U.S. and the U.K.), most intense, and most damaging. Remember that UV light doesn’t only damage your skin, it also damages your eyes and can cause cataracts (commonly) and potentially fatal intraocular melanoma (cancer inside the eye) — wear sunglasses! The CDC has an excellent, and short, webpage on sunprotection here: http://www.cdc.gov/cancer/skin/basic_info/prevention.htm
Sunlight is composed of a broad spectrum of lightwaves (hang with me here) including the visible light that you can see and ultraviolet light (UV) that you can’t. UV light is further composed of UVA and UVB and both of these types of UV light are damaging to your skin, causing it to look old and wrinkled, and potentially can cause skin cancer in people with excessive sun exposure. The SPF of a sunscreen is a measure of how much UVB light the sunscreen blocks under laboratory conditions. Under laboratory conditions an SPF 30 sunblock blocks out approximately 97% of damaging UVB light — the take home message being that if you really want the level of protection that the sunscreen is supposed to provide you better follow the instructions on the bottle. If you think that you’re doing your skin any favors by applying a light coat of SPF 30 sunblock in the morning and then spending 10 hours in the sun without reapplying it every two hours (or whatever the bottle says) you should think again! Remember that SPF only is a rating of protection against UVB light, but UVA is damaging too! Look for a sunscreen that specificially says that it protects against UVA + UVB and don’t settle for anything less.
This is good sunscreen because it has UVA and UVB coverage and it clearly states this on the label. Whether or not an SPF of greater than 30 actually provides greater protection is debatable, but use at least SPF 30 to be safe.
All of this talk about SPF (that’s Sun Protective Factor) immediately begs the question, at least in my mind, as to what the SPF of your skin naturally is and whether the SPF 30 sunscreen recommendation holds for dark skinned people as well as for those of us with lighter complexions. It surprised me to learn that a tanned persons skin only has an SPF of about 4 and an extremely dark skinned person (a black person with very dark skin) still only naturally carries an SPF of about 13 naturally! That’s right, even if you’re as dark as they come you still need to wear sunblock when your outside in the sun or you’re placing yourself at risk of getting skin cancer. While it is true that very light skinned people, especially redheads, are at higher risk for developing a skin cancer (approximately 7x higher risk) than the rest of us, everyone is at risk for this disease and dark skin people tend to be diagnosed later (and with more advanced cancers) because they don’t realize that they can get skin cancer too!
How much protection does this guy’s nice dark tan provide against the sun? Only about SPF 4 — better than nothing, but still pretty darn mediocre.
The Major Types of Skin Cancer
1. Basal Cell Carcinoma: If you absolutely must have a cancer, this is the one to have because it virtually never metastasizes (spreads throughout the body) and it is the metastases that generally make cancers deadly. The downside is that basal cell carcinoma loves to grow in places that are highly visible, like your nose and cheek for instance (notice that these are also highly sun exposed areas!!!), and they can be extremely disfiguring. The only way to get rid of a basal cell carcinoma is to have it surgically cut of your body — and they only get bigger with time, not smaller!
There probably won’t be much of a nose left after this is resected. Keep the plastic surgeon’s in business anyhow…
2. Squamous Cell Carcinoma: Unlike the classic raised and pearly appearing lesion of a basal cell carcinoma, squamous cell carcinoma of the skin likes to form ulcerations. This cancer does metastasize but it is generally slow growing and tends to be curable unless people choose to ignore the large ulceration on their face — which happens more often than you would think (??!!!??!!!??).
3. Melanoma: The granddaddy of all skin cancers and one of the worst cancers that you can possibly get, period. Melanoma loves to spread through the body with a rapidity that is difficult to imagine, being especially fond of migrating to the bone (extremely painful) and the brain (causes delirium, seizures, etc.). This cancer is CURABLE if caught early and surgically resected. There has been some medical progress in the past few years for treating metastatic melanoma but once this cancer migrates out of the skin it remains a death sentence.
Given the size of this unfortunate fellow’s melanoma it is unlikely that it hadn’t metastasized by the time the second photo was taken. Given that the second photo was taken in 2009, it is also unlikely that he is still alive. Melanoma is a devasting disease.
4. Actinic Keratosis and Xeroderma pigmentosa: The girl in the picture below has a genetic condition called xeroderma pigmentosa, or “XP” for short. Everytime you step outside into the sun the sun’s powerful UV rays damage your skin, causing genetic mutations (changes in your skin cells’ DNA). Most of the time your body is pretty good about repairing these mutations, the problem being that every once in a while one slips through the natural repair mechanisms and sticks around inside your skin cells, which then pass it on to new skin cells. Over a lifetime of sun exposure these mutations buildup, just like mutations slowly accumlate in the lungs of long time smokers, and skin cancer (or lung cancer in the case of the smoker) is often the result.
People with the genetic disease xeroderma pigmentosa are born with a defective DNA repair mechanism in their skin and all of that sun damage rapidly results in mutations that, unlike in a healthy person (most of the time, anyhow), don’t get fixed. The result in skin cancer in childhood. People with this disease also suffer from early cataracts, which is why the girl in the picture has cloudy appearing eyes. This unfortunate girl is a potent example of what sun damage does to your skin over time if you don’t take care of yourself — it just happened to her a lot sooner! By the way, the crusted appearing skin lesions on this girl’s face are actinic keratoses, precancerous lesions that each have a 10% chance (in a healthy person) of developing into a skin cancer.
An Important Note: All forms of skin cancer can present in atypical forms, some of which look nothing like the lesions demonstrated above (especially certain types of melanomas). If you have any skin mark/lesion/mole/etc. that is or might be changing, or that is or might be suspicious, get it checked out by your physician!!!
As an aside, the CDC has an excellent webpage detailing the risk factors for skin cancer here: http://www.cdc.gov/cancer/skin/basic_info/risk_factors.htm
Dr. Leonardo Noto
Physician and Author of Medical School 101, Intrusive Memory, The Life of a Colonial Fugitive, and The Cannabinoid Hypothesis. Amazon Link to Doc’s Writing: http://www.amazon.com/Leonardo-Noto/e/B00ATVOMCW/ref=ntt_dp_epwbk_0
NOTE: The Life of a Colonial Fugitive — my dark historical thriller — is free for your ereader at http://www.smashwords.com/books/view/215272. Thanks for reading!
Author Bio: Dr. Leonardo Noto is the nom de plume of a former airborne battalion surgeon who is now in civilian practice. Dr. Noto is the author of four books and he also writes for a medical education corporation that assists medical students, interns, and residents as they prepare for the medical board examinations. Dr. Noto is the proud father of an extremely spoiled 16-month-old American Bulldog who enjoys slobbering everywhere and tearing up things that he is not supposed to! Dr. Noto is an amateur practitioner of muay Thai and Brazilian jiu jitsu and he recently began learning to play the guitar (but he is currently a quite terrible musician, as his neighbors will readily attest).
Remember to discuss all health concerns with your personal physician (I don’t count!) before making any medical decisions. www.leonardonoto.com is intended to present general medical information for entertainment purposes and not as specific guide to any medical treatment. The author has made every effort to present accurate information; however, due to the ever-changing nature of medicine and the intrinsic caveats that are inherent in any particular case, no medical decisions should ever be made based on information gleaned from the internet (duh!). The internet and self-education are great, but they don’t replace your Doc!
The opinions voiced on this medical blog are solely the author’s own and they do not reflect the opinions or values of Dr. Noto’s employers, past or present. Dr. Noto’s medical blogs should never be used as supporting evidence for legal testimony — this is of course obvious to anyone who isn’t a complete moron, but some people are rather stupid.
2. SPF of Black Skin: http://news.bbc.co.uk/2/hi/health/5219752.stm
3. With Sunscreen, Without Sunscreen: http://commons.wikimedia.org/wiki/File:UV_and_Vis_Sunscreen.jpg
4. UVA/UVB Protection Sunblock: http://www.google.com/imgres?imgurl=&imgrefurl=http%3A%2F%2Fwww.walmart.com%2Fip%2FCoppertone-Sport-High-Performance-Ultra-Sweatproof-Sunscreen-SPF-100-4-oz%2F17619676&h=0&w=0&sz=1&tbnid=B65Fwr6SBHb5iM&tbnh=225&tbnw=225&zoom=1&docid=ul9nyaTgmWXhEM&hl=en&ei=yhEdUtzQMYa4qQG7q4DACQ&ved=0CAEQsCU
5. Darkly Tanned Skin: http://en.wikipedia.org/wiki/Human_skin_color
6. Basal Cell Carcinoma: http://en.m.wikipedia.org/wiki/File:BCC_Nodular_type.jpg
7. Squamous Cell Carcinoma: http://commons.wikimedia.org/wiki/File:Squamous_Cell_Carcinoma.jpg
9. Xeroderma Pigmentosa: http://commons.wikimedia.org/wiki/File:Child_suffering_from_Xeroderma_Pigmentosa_(_Rukum_Nepal).jpg