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Skin cancer and the sun

Professor Yaffle

Butterbeans and Breadcrumbs
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Jan 31, 2007
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I have come across arguments several times (possibly all from the same source) that increased exposure to the sun does not cause an increase in malignant melanomas. I read an article about the same thing recently and it reminded me to ask about it here:

Skin cancer statistics are used to scare, not educate. Almost all of the 84,000 skin "cancers" that appear each year are in fact benign: they don't spread or kill; their cancerous name is a historical misnomer. Of course, sun exposure increases facial wrinkling, as does smoking, but the black ace in the fear game is melanoma, because the real thing is vicious.

As the article tells us, Cancer Research UK say the incidence of malignant melanoma has "quadrupled in Britain in the last 30 years". But if this were so we would have seen coffin-loads of consequences by now. We haven't, and in a recently published large UK study (British Journal of Dermatology, 2009), I and my colleagues showed that the reason mortality has not increased with incidence is that the tumours reported are actually benign; they are not true malignant melanomas. Our explanation of the phoney melanoma epidemic is "diagnostic drift which classifies benign lesions as … melanoma", a misdiagnosis "driven by defensive medicine, an unsurprising response to its commercialisation".

<snip>
http://www.guardian.co.uk/commentisfree/2010/jul/21/melanoma-myth-skin-cancer-sun

Has anyone here looked into this before? Is this guy (he's a professor of dermatology) a lone crank in the field using dodgy arguments/methodology, or does he have a valid case?

ETA: Here's a piece from him in the BMJ:
http://www.bmj.com/cgi/content/full/337/jul22_2/a764
 
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Dunno from false diagnoses, but I do read that all the Sun Block has not lowered skin cancer rates. Maybe the false diagnoses are driving up the numbers while the SPF is lowering actual cases?

There is always room for skepticism when the bean counters have a vested interest in counting more beans...
 
I finished reading Dr Holick's book The Vitamin D Solution last week. He is probably the top researcher into vitamin D. He is also a former professor of dermatology at Boston University Medical center. That is what he mentioned in his book, that malignant melanomas were not linked to increased, moderate sun exposure. Basically he said maligant melanomas occurred more often in areas of the body not typically exposed to sun UV rays. Avoid becoming sun burnt he added as that can lead to problems too.

A good review of Dr Holick's book can be read at:

http://www.proteinpower.com/drmike/supplements/sunshine-superman/
 
Almost all of the 84,000 skin "cancers" that appear each year are in fact benign: they don't spread or kill; their cancerous name is a historical misnomer.
The author posted a retraction of that on 28 July 2008 in the rapid responses.

He deletes the "benign naevi" remark.

The quote in the OP implies only melanoma is of concern. All skin cancers are of concern & potentially deadly if they are not treated, though some are very slow growing, according to my dermatologist.
 
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If skin cancer is not related to exposure to the sun, why are rates so high in Australia? http://www.actcancer.org/sun-smart/skin-cancer.aspx

Australia has one of the highest rates of skin cancer in the world. This is due largely to our climate, the fact that many of us have fair skin that isn’t suited to such harsh conditions, our proximity to the equator and of course our social attitudes and love for the great outdoors. Each year over 1700 Australians will die from skin cancer

My father-in-law, a farmer, had his skin cancer caught just in time. He could well have died.
 
A solar physicist friend of mine likes to point out that most people, if they stood close enough to a hydrogen bomb blast to redden their skin from radiation burns, would consider that something pretty alarming had happened to them. Yet, millions of them do just that, deliberately, every summer's day.
 
A solar physicist friend of mine likes to point out that most people, if they stood close enough to a hydrogen bomb blast to redden their skin from radiation burns, would consider that something pretty alarming had happened to them. Yet, millions of them do just that, deliberately, every summer's day.

They would be burnt from different wavelengths of the EM spectrum.
 
Cancer isn't anything to take lightly, but doctors have known for awhile that nonmelanoma skin cancer is related to sun exposure. It can be fatal but rarely is.

My dermatologist doesn't even refer to my skin cancers as cancer; he calls it "sun damage".
 
Well I can give you the information I have from working here at the Dana Farber Cancer Institute.

Melanoma is in fact very dangerous. It is actually cancer. That's the bad news.

The good news! If caught early, it has a virtually 100% cure rate. Melanoma in situ is the earliest stage, and it means the cancer is restricted to the area where you can see it, on the surface of the skin. Melanoma in situ is usually easily excized from the patient's skin. Often patients will have recurrent melanomas, the doctor will just keep slicing them off, and the patient is perfectly fine afterwards.

However, left untreated, Melanoma is very dangerous. At stage III it has spread to the lymph nodes. By stage IV, survival rate is around 10-15%.


The thing with cancer is so much depends on how long it takes before it is diagnosed. With many cancers, by the time the patient becomes symptomatic and realizes anything is wrong, the cancer is so advanced that survival rates have plummeted. The good thing about skin cancer is that, unlike, say, pancreatic cancer, you don't have to wait until you become symptomatic. You can SEE the cancer on your skin, and have it taken care of.

That is why it is so important to have moles or unusual spots on the skin checked up on, so if they become cancerous, you can slice that bugger off before it causes you any real damage.
 
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And Melbourne is as close to Darwin as you are to Maine.

Your grasp of geography needs a little work.
Actually, no, it's not; you're off by a few hundred miles, but thanks for the gratuitous abuse.
 
The author posted a retraction of that on 28 July 2008 in the rapid responses.

He deletes the "benign naevi" remark.

The quote in the OP implies only melanoma is of concern. All skin cancers are of concern & potentially deadly if they are not treated, though some are very slow growing, according to my dermatologist.

The bit I quoted was from an article from July 2010.

I'm going to read up a bit more on this and come back when I have some more time (may be a while) and argue as if I accept he is correct, and see how his individual arguments hold up.
 
If skin cancer is not related to exposure to the sun, why are rates so high in Australia? http://www.actcancer.org/sun-smart/skin-cancer.aspx

I remember reading a while back that skin cancer is often linked to lymphoma. At the time it had just been discovered that, not only were people who were prone to skin cancer also prone to lymphoma, but people who spent more time in the sun got lymphomas more often.
 
I started getting skin cancers in my early thirties -- basal cell carcinoma. However, as I get older, the basal cell cancers are giving way to squamous cell carcinoma.

In her book "Another Day in the Frontal Lobe", Katrina Firlik described a patient who had a squamous cell cancer on his face. He was homeless and didn't get any medical attention. When the cancer became infected and disfigured his face, he wrapped a cloth around it. Years later, when a police officer finally noticed how bad off he was, the poor guy was finally taken to the hospital. The cancer and infection had destroyed one eye, eaten through his skull, and exposed his brain, which was being happily munched upon by maggots.

Dr. Firlik said when she examined the patient it was the only time in her career that she wanted to throw up.

So...not melanoma, but it shows the extremes of what untreated skin cancer can do.
 
Melbourne is about as close to the Equator as San Francisco.

And Melbourne is the furthest major city from the equator in the entire country. I think you'll find that melanoma rates are higher cities closer to the equator, such as Brisbane.
 
Melbourne is lionking's location. :rolleyes:

Ah... so you singled out lionking's location because by quoting from an article by the Cancer Council that mentions "our climate", he was obviously referring to his own specific city rather than referring to the country as a whole? :rolleyes:
 
My point was that, although none of us knows where lionking's father in law lives, if he lives close to lionking then proximity to the Equator is not a factor since Melbourne is about as close to the Equator as San Francisco.

In general, Australia is not particularly special among populated regions of the world because of its supposed proximity to the Equator. To see that, just bring up Google Earth, click on View, checkmark Grid, and compare the absolute values of latitudes. Notice that only about half of Australia is in the Tropics. On top of that, other sources show that most of the population is concentrated in the southern, temperate half.

In conclusion, I apologize if I offended anyone with my skepticism... Oh, wait, this is JREF, isn't it? I don't need to apologize for that! ;)
 
Yes but the Earth's orbit is not actually concentric, bringing us closer to the sun during the southern hemisphere's summer, and further from the sun during the northern hemisphere's summer. So Australian summers are warmer than US summers, with greater UV too.

I suppose this changes over eons, perhaps affecting ancient climate proxies, but I don't know how long the cycles are.
 
Yes but the Earth's orbit is not actually concentric... (etc.)
There were additional reasons given for higher skin cancer in Australia in lionking's post, and now you're offering yet another one. That's fine. I'm not disputing any of those reasons nor am I disputing that incidence of skin cancer is, in fact, greater in Australia. All I'm disputing is that proximity to the Equator is a legitimate reason.
 
If all you're saying is that proximity to the equator doesn't make Australia particularly special in regards to rates of skin-cancer, that's fine. It just wasn't clear from your posts that this is what you meant.

But to change the subject slightly, there are other factors involved UV-related cancer in Australia, such as more UV light reaching us through ozone depleted pockets of air from the hole in the ozone layer.

Bureau of Meteorology said:
Does the ozone hole ever come over Australia?

After the ozone hole has broken up parcels of ozone depleted air mixed with mid latitude air move north. These parcels can move over the southern part of Australia, though their effect is far less pronounced than the effect of the ozone hole.
http://www.bom.gov.au/climate/glossary/ozone.shtml#overaustralia

The good news is that the hole in the Ozone layer will probably be completely healed somewhere around 2075.

http://www.radioaustralia.net.au/pacbeat/stories/200909/s2695052.htm
 
Still haven't seen anything to counter the prevailing scientific opinion that skin cancer is related to exposure to the sun.
 
If skin cancer is not related to exposure to the sun, why are rates so high in Australia? http://www.actcancer.org/sun-smart/skin-cancer.aspx



My father-in-law, a farmer, had his skin cancer caught just in time. He could well have died.

Sun exposure increases basal cell and squamous cell carcinoma, but the link with melanoma and skin cancer is very tenuous.

The issue is that people think 'skin cancer' is one disease when there are three basic types of cancer with a very different prognosis.

This is a common problem in 'cancer', as every single cell type in our body can become cancerous, and each one is different disease, however, the majority of the public think it is just one disease.

The majority of skin cancers are the squamous and basal, which is good as they are not as nasty as malignant melanoma.
 
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Sun exposure increases basal cell and squamous cell carcinoma, but the link with melanoma and skin cancer is very tenuous.

The issue is that people think 'skin cancer' is one disease when there are three basic types of cancer with a very different prognosis.

This is a common problem in 'cancer', as every single cell type in our body can become cancerous, and each one is different disease, however, the majority of the public think it is just one disease.

The majority of skin cancers are the squamous and basal, which is good as they are not as nasty as malignant melanoma.
Thanks Tatyana. I will research this a bit more.
 
The forum software is currently listing this thread as "trending content."

Perhaps it knows something we don't? Like, have there been any interesting new findings regarding sun exposure and skin cancer over the past fourteen years?
 
have there been any interesting new findings regarding sun exposure and skin cancer over the past fourteen years?
Yes. More bad news for red heads: Even without exposure to UV rays, they're are more likely to get skin cancer than other people:
Ginger Gene and Suncare for Red Heads (APDerm, Aug 17, 2020)
Researchers also found people with one copy of the crucial MC1R gene – who may be fair-skinned but not have red hair – also have a higher risk for skin cancers. Additional research has found people with the faulty MC1R gene have cancer-causing mutations unrelated to sunlight, meaning other factors are likely at play.
 
Global warming, loss of ozone layer?
For the past 14 years, the ozone layer hasn't experienced a loss. On the contrary:
Ozone layer recovery is on track, helping avoid global warming by 0.5oC (UN Environmental Programme, Jan 9, 2023)

I don't think global warming contributes to skin cancer. The problem with CO2 emissions is that they make the atmosphere retain heat, i.e. not let heat (unlike UV rays) escape into the void surrounding Earth. But I could be wrong.

ETA: And apparently I am. Not entirely, but ...
Hotter summers may fuel increase in skin cancers, doctors warn (TheGuardian, Aug 5, 2022)
“One of the clearest signals of climate change is hotter temperatures, not just in summer, but all year around,” he said. “This shift in temperatures also shifts behavioural patterns, and people in the UK tend to go outside more when the temperatures are warm. This leads to more exposure to sunlight throughout the year, and crucially more exposure to the UV part of that sunlight, which is a known risk factor for skin cancer.”

Impact of climate change on skin cancer (JRSM/NIH/PubMed, June 1, 2009)
The increase in temperature could make the carcinogenic effects of UVR even more lethal. Mouse experiments have shown that the carcinogenic effectiveness of UV radiation increases by 5% per °C, so a long-term elevation of temperatures by 3.5°C would increase the carcinogenicity by 7.5%.
 
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