Dueling Docs - Does the Sun Really Cause Melanoma?

The Issue
Melanoma has always been considered linked to sun exposure, and sunscreen thought to protect against it. Now some doctors raise doubts.

The Facts
When most Americans think of melanoma, they think of John McCain as a POW baking in the Vietnam sun and developing such a severe form of the deadly skin cancer that his face was left scarred and oddly puffy. But is the sun really to blame?

Medical experts agree that sun can cause wrinkling, mottled pigmentation and generally age the skin, but now some researchers wonder if UV rays have anything to do with melanoma. They suggest there may not be a link, even though the rates of melanoma have gone up by 3.1 percent a year since 1992, coinciding with a thinning ozone layer. Indeed, this year, according to the National Cancer Institute, there will be 68,720 new cases of melanoma and 8,650 people will die from the disease. The risk of melanoma is more than 10 times higher for whites than for African Americans, particularly for fair-skinned Caucasians with red or blond hair who burn easily. Nevertheless, detractors say sunscreen won't do a thing to protect them.

Two doctors debate the issue. Sam Shuster, dermatologist and honorary consultant at Norfolk and Norwich University Hospital in the UK and Scott Menzies, dermatologist and associate professor at the University of Sydney, Sydney Melanoma Diagnostic Centre in Australia

The Debate

Dr. Shuster: "First of all, let's forget the politicians. It's rather arrogant for John McCain to make any assumptions about why he developed his melanoma. I'm surprised people believe anything politicians say anyway."

"All the scriptures about sun exposure and melanoma are premature. The UV explanation for melanoma is not adequate."

As evidence, Shuster says that "Melanoma cases occur on relatively unexposed sites of the body, especially the feet of dark-skinned Africans. There is no evidence that melanomas occur at sunburn sites on the body. Meanwhile, it's difficult to create melanomas in laboratory experiments with ultraviolet light, suggesting that UV has little impact."

Shuster acknowledges that the sun is responsible for some skin cancers, like basal and squamous cell, but, says he, "these are virtually benign and mostly trivial."

"Like smoking," says Shuster, "the sun makes the skin look as if it has been well lived in. But, there is no proof that ultraviolet light exposure is a significant cause of the rarer, truly malignant melanoma."

"If sun were important," he goes on, "we'd expect sunscreen to decrease the incidence of melanoma over the years as more and more people are using sunscreen. But that hasn't happened. Melanoma has actually increased."

Shuster suggests that the sun may actually decrease the risk of melanoma. "That's why we're seeing more melanoma cases in spite of the popularity of sunscreen. I have no hypothesis, but we do know that a substantial number of studies show an increased risk of melanoma with the use of sunscreen. Maybe the vitamin D from the sun protects against melanoma? All sorts of things are possible. There could be a bad fairy living in Mars, but that doesn't mean melanoma is related to sun exposure."

Does Shuster see a role for sunscreen then? "Well, we do know the sun makes us feel better, although we don't know how, and we do know that we need skin synthesis of vitamin D for our bones and that sun has important, unexplained immunological effects. But, if you burn and you live in a sunny environment and you want to use sunscreen, then go ahead."

Dr. Menzies: "To me this is a sort of flat-earth argument. Let's look at the real evidence here. It's true that in dark-skinned people, like the Asian and black populations, melanoma shows up in areas of the body that are not exposed to the sun and this certainly could suggest that melanoma is not related to UV light. In white-skinned races, we also see that 1% of melanomas are found in areas not-exposed to the sun. But in these cases, it's a different disease -- and a very rare one. What we do know is that melanoma is highly dependent on how much sun you get and your tendency to get sunburned. In the end, 95% of melanoma cases are due to sun exposure"

"To argue against this is like saying lung cancer is not caused by cigarettes because some people get lung cancer even though they don't smoke. It's exactly the same logic."

"We also know that the relative density or severity of the melanoma is greater on body sites that get more sun, like the trunk in men and lower extremities in women."

"Actually, the best predictor for melanoma is not total sun exposure, but hard and intermittent exposure that does the damage. Your cells don't develop adequate protections when your exposure is erratic."

"As for sunscreens, yes, it is correct to say that there is no evidence that sunscreens protect against melanoma. But there's a reason. People who wear sunscreens think they can spend more time in the sun and so they do. That's what increases their exposure to UV light and that's why sunscreens don't appear to be protective. Sunscreens are also used wrong all the time. To protect again melanoma and other skin cancers, sunscreen has to be applied properly. Apply a thick layer ½ hour before going out into the sun and reapply every two hours or after swimming or sweating. The higher the sunscreen, the greater the protection, so try to use a SPF of 30 or more."

Comments

[mergina]

Interesting different opinions. In my case, the two melanomas removed from me were on my shoulders and back that as a child, was burned at least once a year. As kids we lived in the sun. Love that Vitamin D. Hate those Melanoma surgeries.

[timezone]

As someone who lives in the Southwest, is very fair-skinned and has had basal cell carcinoma removed three times and pre-cancer on my back once, I'll go with the theory that the sun probably does cause skin cancer, all types. My dermatologist told me it's not just about our sun exposure now, but the burns we had before the age of 15. I do wear sunscreen, particularly on my face.

[GracieBoy]

It is amazing that there are so many areas in medical science that we take as given but are actually uncertain. I think we need to breed people for medical testing like we do mice, and then we can get more certianty on these various fronts.

Until we do that -- and I don't think it will happen in this administration -- it seems to me that whether a lot of sun causes melanoma or not, while academically interesting, doesn't really matter in terms of action to take. We should be careful in the sun.

If nothing else, look at all of these old ladies, you know, women who are mid-forties and on, who look all wrinkled from their Hamptons and Country Club life style. I don't want my girlfriend looking like that when she gets old.

[Jan Alexander]

Fascinating and scary. I'm not at all saying that this is a lesson for the rest of us, but my dermatologist likes to go sailing in the Carribean and comes back tanned.

[Pearlswan]

I didn't see any scientific evidence in this article to support either side. It is just two opinions with no studies to back up either. However, it is known that sunscreen is destroying the coral reefs. If it kills coral reefs can it really be good for our skin? And, this stuff is getting poured onto our childrens' skin these days like its safe and harmless. Scary. And, there is an epidemic of Vitamin D deficiency in the US population now since the heavy use of sunscreen began in the 1980s. There is evidence for the death of coral reefs and the link to sunscreen and there is evidence for Vit. D deficiency and the increased use of sunscreen. The best sunscreen, in my opinion, is shade. Chemicals should be avoided, if possible.

[marlovian]

Remember to remove that sunscreen before swimming near coral reefs:

http://www.environmental-expert.com/resultEachPressRelease.aspx?cid=8819&codi=32053&idproducttype=8

[cktirumalai]

Alexander Pope asked ironically, "When doctors disagree who shall decide?" By doctors he seems to have meant learned people.
There are other dilemmas. We are told that lack of Vitamin D is a problem in many cases, and that it is frequently due to our not being in the sun enough. It is beginning to look like a case of "Damned if you do, damned if you don't." Conflicting medical advice can leave people in a maze. For myself I think Dr. Menzies more convincing.
Incidentally Sun-worship was once a celebrated religion, vying with Christianity for dominance.

[Janice Horowitz - Huffpost Blogger]

My advice - and I'm not a doctor - is to get a dose of sun for Vitamin D in the morning before 10 a.m. Just fifteen minutes will give you D - and Vitamin D stores in your body for months. At least that's my understanding. After 10 am, smear on the sunscreen.

[csepwede]

speaking as a brown skinned woman, I can't for the life of me see how smearing chemicals on your skin repeatedly can be healthy for your skin.

[csepwede]

I don't use sunscreen. don't believe it's healthy.

[FLAPPDOODLE]

What if melanomas were caused by, say, sun tan oil or some other cosmetic reacting with the sun? Something perhaps that people started using coincidentally at the same time the ozone layer was thinning?

[Janice Horowitz - Huffpost Blogger]

It's a thought. Especially now that sunscreens apply so easily, some people believe that the active chemicals are more micronized and therefore more easily absorbed in the skin. That's one theory at least.

[Formind]

Going back to sunscreen itself:

What is a sunscreen? I read the ingredients of three popular-brand sunscreens I have in my cabinet (all with an SPF of 30). There's no replication of any active chemical and two products don't list chemical concentration levels. Inactive ingredients cover a wide spectrum including but not limited to Glycol, Diazolidinyl Urea, Oat Beta Glucan, Propylaparaben etc. etc. etc.

To the best of my knowledge, study findings haven't been reproducible; science has yet to identify and standardize a specific or group of active chemicals that do in fact offer UV light protection­/buffering­.

Meanwhile the " Sunscreen and Skin Protection" aisle at the Duane Reade store near me keeps growing and growing...