Many Melanoma Survivors Skip Sunscreen

[tim-from-pa]

http://www.webmd.com/cancer/news/20...melanoma-survivors-skip-sunscreen-study-finds

In the article, a troubled dermatologist lamented,

"It is certainly concerning that a quarter of the melanoma survivors never wear sunscreen..."

Hmmmmm. I wonder why? I wonder if they are through (as I am) with all the "sun is bad" tripe? I wonder if they are the ones that found out that Melanoma actually increased, not decreased in recent years after they been dutifully sloshing on the sunscreen mess? or again if they found out if the sunscreen itself has something like 4 known carcinogens, and that a lot of Melanoma shows up in places that the sun does not shine?

They (and most of us) were never told things like this.

And I would not be surprised if those 1/4 of the people were actually putting on sunscreen beforehand and maybe got disillusioned? Wouldn't that be ironic? But rest assured, if that was the case, the media, medical establishment and Big Pharma would not agree to that being put out in the open and would prevent them from saying so.

Face it folks, sunscreen is a big business. There's $$$$$$$$$$$ otherwise I can't see why the medical establishment would want us all to avoid the sun and be locked away like Dracula, lest we melt to skeletons when it hit us.

Now, here's a site better spending you time with, rather than wasting your time on medical tomfoolery.

http://sunlightinstitute.org/

 

[Knotical]

There are also toxic substances in the sunscreen, which partially attributes to skins cancer. You are almost better off either going without, or finding a more holistic approach.

 

[tim-from-pa]

There are also toxic substances in the sunscreen, which partially attributes to skins cancer. You are almost better off either going without, or finding a more holistic approach.

Agreed. How about a big hat or beach umbrella to take a break from the sun? Nobody's saying roast yourself in the sun, and never have over the years, but the info out there is downright hostile against the sun as if you'll get skin cancer if you so much as take a few minutes to dart to your car without sunscreen. Totally ludicrous.

Like that sunlight site stated, the sun's been doing it's job quietly for the last 4 billion years and never needed a marketing department. Now it does. :silly :rolling

 

[Knotical]

We could always take a cue from Kramer. Slather ourselves in butter. We could give ourselves a nice golden brown tan.

 

[reba]

Not taking the time to look this up but I seem to remember hearing no sun causes rickets ... "THEY" have not yet figured out how to sell sunshine when "THEY" do it will be good for you again!

 

[Obadiah]

Yep, I've heard of these problems with sunscreen, as well as the problems that come about from extreme lack of sun exposure. I couldn't believe it when I went into the drugstore last summer up here in the Pacific Northwest to by some sunscreen. I wanted #4 because that always gives me plenty of protection up here where the sun's not really all that strong. They only had like ONE brand that had a number that low! Some of them had an SPF number of 100!

Now I've been told that the SPF number means that's based on the amount of time it will take to get the equivalent sun exposure that you would get with no sunscreen. For example, with SPF 4 it would take 4 hours of sun exposure to get the same effects that you would get in 1 hour with no protection. Well, if that's true, at SPF 100 I would have to have a full 9 hours of uninterupted sun exposure to get the effect of just a bit more than 5 MINUTES in the sun unprotected! This is crazy paranoia!!!

Yep, the fanaticism is rampant. It seems with many, trying to discuss it with them is like trying to discuss religion or politics!

 

[tim-from-pa]

Not taking the time to look this up but I seem to remember hearing no sun causes rickets ...

Yes, that's true because of the vitamin D deficiency. The sun is the best way to get vitamin D, far better than swallowing pills.

 

[tim-from-pa]

The amount of sun exposure one needs really depends on the individual. Some here have very fair skin and burn easily, in which case a few minutes would be enough for them. I do feel sorry, though, that they can't just go outside for even a short time to enjoy themselves without that becoming an issue, because nobody wants anyone to burn.

On the other hand, I can go for hours without my shirt on, but typically to do some outdoor chores or mow the lawn which may take no more than 2 hours, as I am not one inclined to work more than that at a time anyway. (Heck people don't jog for 2 hours let alone do strenuous outdoor work for that long without at least a break for awhile). At worst, I'll be a little red which I can feel in the shower the next day, but it disappears in a day, and this is only early in the season before my naturally produced, bodily sunblock kicks in. Once I tan, this is not as much of an issue. My skin is darker, and guys like me, and even my darker Afro-American brothers do need more, maybe at least an hour to get the same effects as 15-20 minutes. Dark skinned people are more vitamin D deficient since their pigmentation blocks a lot of the UV, and the fact that we are darker shows that the body does produce it's own protection. But it will never be engaged if we basically stay out of the sun and/or put on sunblock all the time.

 

[duari91]

I don't think people need to worry so much. Of course, it is not good to be reckless, but come on. Anything can give you cancer.

If you live long enough, you will get a cancer of some sort.

That's like drinking diet soda to protect you from the sugar in the regular soda. You will die much sooner from cancer that the diet soda gives you, rather than the sugar in the regular version.

As you can tell, I have a bone to pick with most health nuts. Not because they wan't to live healthy, but because they usually start a sentence with "Dr.Oz says...."

 

[tim-from-pa]

In my first post I stated:

I wonder if they are through (as I am) with all the "sun is bad" tripe? I wonder if they are the ones that found out that Melanoma actually increased, not decreased in recent years after they been dutifully sloshing on the sunscreen mess? or again if they found out if the sunscreen itself has something like 4 known carcinogens, and that a lot of Melanoma shows up in places that the sun does not shine?

Then I came across this article today:

http://www.sci-tech-today.com/news/...story.xhtml?story_id=032000OE23XC&full_skip=1

On page two of the article, they made this "surprising" statement (well, not surprising to me):

"When someone is first diagnosed, they are practicing sun protection, but as the years go by, maybe they tend to fall back on their old habits," she says. "A lot of melanoma survivors have told me that it is very important for them to maintain a normal outdoor lifestyle."

Tend to fall back???? No, it's like I said, they WERE sloshing on the gunk believing the tripe that "the sun is bad" and became more disillusioned is more like it. If we look at history, we don't see people falling over with Melanoma who spent countless more hours in the sun; so much for the "genetics" the health field blames it on.

They accuse those who do not admit to it being the sun are in "denial". No, it's the self-assured establishment who can't get off their academic high-horse long enough to humble themselves to admit they were wrong all along that are in denial --- telling the people to protect themselves, which they have been doing, and are now sicker and more cancerous than ever. Then.... there's that money thing, too, I mentioned.

 

[elizabethbraddock]

I think there is a misunderstanding here about the mechanism of how sunlight increases cancer risk. Obviously, sunlight exposure is required for vitamin D synthesis, which is necessary as a gene transcription factor to increase the expression of calcium channels in the lumen of the small intestine, leading to increased absorption of calcium. However, sun exposure is also a risk factor for cancer because UV rays cause DNA damage, which has been demonstrated; UV rays can cause a photochemical reaction that causes pyrimidine dimers to form. The most common pyrimidine dimer is a T-T dimer, where adjacent thymine base pairs are joined together, disrupting the structure of the DNA at that location. This is normally repaired by a DNA repair mechanism known as nucleotide excision repair, and usually works quite well, unless the genes that encode the repair mechanisms or genes that control the expression of the repair mechanisms are damaged. The body also has a natural defense mechanism against UV-induced DNA damage; when exposed to UV rays, such as exist in sunlight, specialized cells known as melanocytes produce the pigment melanin, resulting in a tan. The melanin is transported to skin cells and accumulates on the face of the nucleus facing the UV exposure, forming an umbrella that shields the DNA from the UV radiation. Repeated excessive sun exposure over the course of a lifetime leads to an accumulation of DNA damage that can lead to cell proliferation, and skin cancer.

The UV in sunlight is strongly associated with skin cancer; populations that are along the equator and naturally have higher amounts of melanin in the skin have much lower incidences of skin cancer versus fairer skinned populations in the north which have higher incidences of skin cancer.

But you are correct that sunscreens can also contribute to cancer risk; most sunscreens contain aromatic, organic compounds that absorb the energy from the UV rays, but do not dissipate it as well as melanin can. This lead to the production of reactive oxygen species which also damage DNA. Best way to protect yourself from the sun is to wear clothing that covers the skin and wearing hats.

 

[tim-from-pa]

I think there is a misunderstanding here about the mechanism of how sunlight increases cancer risk. Obviously, sunlight exposure is required for vitamin D synthesis, which is necessary as a gene transcription factor to increase the expression of calcium channels in the lumen of the small intestine, leading to increased absorption of calcium. However, sun exposure is also a risk factor for cancer because UV rays cause DNA damage, which has been demonstrated; UV rays can cause a photochemical reaction that causes pyrimidine dimers to form. The most common pyrimidine dimer is a T-T dimer, where adjacent thymine base pairs are joined together, disrupting the structure of the DNA at that location. This is normally repaired by a DNA repair mechanism known as nucleotide excision repair, and usually works quite well, unless the genes that encode the repair mechanisms or genes that control the expression of the repair mechanisms are damaged. The body also has a natural defense mechanism against UV-induced DNA damage; when exposed to UV rays, such as exist in sunlight, specialized cells known as melanocytes produce the pigment melanin, resulting in a tan. The melanin is transported to skin cells and accumulates on the face of the nucleus facing the UV exposure, forming an umbrella that shields the DNA from the UV radiation. Repeated excessive sun exposure over the course of a lifetime leads to an accumulation of DNA damage that can lead to cell proliferation, and skin cancer.

The UV in sunlight is strongly associated with skin cancer; populations that are along the equator and naturally have higher amounts of melanin in the skin have much lower incidences of skin cancer versus fairer skinned populations in the north which have higher incidences of skin cancer.

But you are correct that sunscreens can also contribute to cancer risk; most sunscreens contain aromatic, organic compounds that absorb the energy from the UV rays, but do not dissipate it as well as melanin can. This lead to the production of reactive oxygen species which also damage DNA. Best way to protect yourself from the sun is to wear clothing that covers the skin and wearing hats.

Welcome back. I have not heard from you for awhile. How's the studying going?

Anyway....

Let's ask this rhetorical question. First of all we know that the body can produce its natural sunscreen (melanin). Could the real problem be (which is what I was hinting at) that the population does not any longer produce natural defences the way generations ago did who stayed out in the sun without as much of a health issue? And if so, why is that? Diet altering genetics?

Let's use an analogy as to what I see happening here.

Let's compare #2 home heating fuel oil to a person. When atomized, it heats the house nicely when a spark ignites it. But have an open liquid container of it I can through in matches all day and it won't ignite to an open flame, nor make an existing flame much larger if put onto the fire.

Now, mix that fuel oil with some gasoline and watch how a match will flare it up. So, we blame the matches in this case? No, something changed in the oil making it more flammable, and to use it we have to somehow purify it again.

If people are truly burning up in the sun and getting all this cancer, we have to ask ourselves what really changed? But then that gets off on the processed foods and drug tangents again, and the answer is not to cut off the sun, the giver of life, but rather to fix the person up because if the sun doesn't give it to them, then something else will and we can't avoid everything like a monk.

 

[Claudya]

So trying to compile all the information from this thread and some internet research about sunlight, sunscreen and skin cancer:

- since indoor people are more likely to get skin cancer than outdoor people it's probably a question of how well a person's skin is adapted to sunlight
- thus controlled exposure and healthy nutrition is better than sunscreen because sunscreen will hinder the natural skin protection mechanism (Vit D/ melanine), it may trick people into staying in to sun way too long (because they think they are protected more than they actually are) and it can actually make carcinogenic substances form in your skin and thus do the opposite of what it claims to be.
- it's important to avoid sunburns because they do a large amount of cell damage (and also they hurt and look ugly), but completely avoiding unprotected sun exposure would actually be bad. Again it's only a question of what your skin is used to. If one spends a lot of time outdoors (construction worker or farmer or so) they're already well protected by their own very skin.
- sunscreen should only be used if you are exposed to a huge amount of sun (way more than you are used to) and can't avoid the exposure through clothing or seeking shadow. But use of sunscreen should be an exception and not everyday business.

Is that about right?

 

[tim-from-pa]

So trying to compile all the information from this thread and some internet research about sunlight, sunscreen and skin cancer:

- since indoor people are more likely to get skin cancer than outdoor people it's probably a question of how well a person's skin is adapted to sunlight
- thus controlled exposure and healthy nutrition is better than sunscreen because sunscreen will hinder the natural skin protection mechanism (Vit D/ melanine), it may trick people into staying in to sun way too long (because they think they are protected more than they actually are) and it can actually make carcinogenic substances form in your skin and thus do the opposite of what it claims to be.
- it's important to avoid sunburns because they do a large amount of cell damage (and also they hurt and look ugly), but completely avoiding unprotected sun exposure would actually be bad. Again it's only a question of what your skin is used to. If one spends a lot of time outdoors (construction worker or farmer or so) they're already well protected by their own very skin.
- sunscreen should only be used if you are exposed to a huge amount of sun (way more than you are used to) and can't avoid the exposure through clothing or seeking shadow. But use of sunscreen should be an exception and not everyday business.

Is that about right?

Yep.

The last point I would opt for protective clothes (a loose, reflective shirt for example) and things like hats and beach umbrellas and only use the sunscreen to prevent burning if for some reason you are in the sun for a prolonged period of time and can't get protective clothes for some reason, which is probably not often enough to be a problem anyway. You are correct.

 

[tim-from-pa]

To everyone else:

Claudya has a lot of commonsense and intelligence on this matter. And I agree with her, as I hope my mentioning the sun is not misconstrued to mean baking yourself in it until you look burned like that lady who was in the news a few months ago where they took her kid away for having a bad sunburn. Anti-sun activists will use that extreme to convolute the message that the sun is healthy into a radical concept like that woman did and apply it to EVERYONE who speaks the sun's praises. That's because these anti-sun people are just as radical, but in the opposite. They want you to avoid all sun, and if you are without sunscreen, don't expose yourself more than the time it takes to run to your car from your house. And put it on even in the winter, etc etc. This is not commonsense or science, but blatant radicalism. Why, what ever happened to the people out mowing their lawn in the sun? Or the housewife hanging her laundry to dry? Did they need sunscreen the way these people say you need it today? Of course not. But people did use "sun tan lotion" (I still call it that --- shows my age! ) to prevent burning for long days at the beach --- that's been with us a long time. That's different, although clothing is better.

Frankly, I never met a person as baked from the sun as that woman was. Has anyone here? And to compare that to a person who wants a little sun by scaring them with those pictures is downright ludicrous.

So.... why can't people see things more clearly like Claudya and hit a proper balance?

 

[elizabethbraddock]

Thank you, it's good to be back. Studying is going fine, but keeping me very busy. Your bring up some good concerns, let me try to address them.

The real problem is not that melanin is no longer effective, it is. Melanin acts as a barrier to protect the DNA in the nucleus from damaging UV radiation. There are a couple of reasons that we see an increase in sun cancer incidence:

1) Age. People are living longer these days than in the past, and cancer is caused by genetic mutations that affect the cell's ability to regulate it's growth, causing them to proliferate uncontrollably. A longer life span means more mutations can accumulate over a lifetime, increasing the rate of cancer appearance in an aging population. Cancer doesn't start overnight and is the result of a many years of accumulated DNA damage.

2) Environmental factors and nutrition definitely play a factor in many types of cancer, but the largest single contributor to skin cancer, specifically, is overexposure to UV radiation. This can be demonstrated not only in the lab, but by epidemiological data. We know that people who naturally have a high melanin content in their skin, such as blacks and other ethnic groups with darker skin, have very low prevalence of skin cancer. Fair skinned individuals that lack melanin have higher incidences of skin cancer. This isn't a problem in places like Northern Europe where the sun isn't harsh, but when these populations are transported to a different portion of the world their incidence of skin cancer increases. For example, Europeans that have immigrated to Australia or New Zealand, which lie along the equator and have extreme sun exposure, have much higher skin cancer incidences than their European counterparts--in fact, four times higher than in the US, UK, and Canada.

Processed foods and chemical exposure play a very small role in the development of skin cancer, but they are large contributors to other types of cancers. But that is for another discussion sine this thread is about skin cancer.

Welcome back. I have not heard from you for awhile. How's the studying going?

Anyway....

Let's ask this rhetorical question. First of all we know that the body can produce its natural sunscreen (melanin). Could the real problem be (which is what I was hinting at) that the population does not any longer produce natural defences the way generations ago did who stayed out in the sun without as much of a health issue? And if so, why is that? Diet altering genetics?

Let's use an analogy as to what I see happening here.

Let's compare #2 home heating fuel oil to a person. When atomized, it heats the house nicely when a spark ignites it. But have an open liquid container of it I can through in matches all day and it won't ignite to an open flame, nor make an existing flame much larger if put onto the fire.

Now, mix that fuel oil with some gasoline and watch how a match will flare it up. So, we blame the matches in this case? No, something changed in the oil making it more flammable, and to use it we have to somehow purify it again.

If people are truly burning up in the sun and getting all this cancer, we have to ask ourselves what really changed? But then that gets off on the processed foods and drug tangents again, and the answer is not to cut off the sun, the giver of life, but rather to fix the person up because if the sun doesn't give it to them, then something else will and we can't avoid everything like a monk.

 

[elizabethbraddock]

I agree, appropriate clothing to protect from the sun is much better than using sun screens; I had actually said that in my original post, but it looks like no one noticed. I pretty much said everything Claudya said, but in scientific terms.

I think only people are are extreme would advocate staying out of the sun completely; that's just silly. Like everything else in life, moderation is key.

To everyone else:

Claudya has a lot of commonsense and intelligence on this matter. And I agree with her, as I hope my mentioning the sun is not misconstrued to mean baking yourself in it until you look burned like that lady who was in the news a few months ago where they took her kid away for having a bad sunburn. Anti-sun activists will use that extreme to convolute the message that the sun is healthy into a radical concept like that woman did and apply it to EVERYONE who speaks the sun's praises. That's because these anti-sun people are just as radical, but in the opposite. They want you to avoid all sun, and if you are without sunscreen, don't expose yourself more than the time it takes to run to your car from your house. And put it on even in the winter, etc etc. This is not commonsense or science, but blatant radicalism. Why, what ever happened to the people out mowing their lawn in the sun? Or the housewife hanging her laundry to dry? Did they need sunscreen the way these people say you need it today? Of course not. But people did use "sun tan lotion" (I still call it that --- shows my age! ) to prevent burning for long days at the beach --- that's been with us a long time. That's different, although clothing is better.

Frankly, I never met a person as baked from the sun as that woman was. Has anyone here? And to compare that to a person who wants a little sun by scaring them with those pictures is downright ludicrous.

So.... why can't people see things more clearly like Claudya and hit a proper balance?

 

[tim-from-pa]

The real problem is not that melanin is no longer effective, it is. Melanin acts as a barrier to protect the DNA in the nucleus from damaging UV radiation. There are a couple of reasons that we see an increase in sun cancer incidence:

1) Age. People are living longer these days than in the past, and cancer is caused by genetic mutations that affect the cell's ability to regulate it's growth, causing them to proliferate uncontrollably. A longer life span means more mutations can accumulate over a lifetime, increasing the rate of cancer appearance in an aging population. Cancer doesn't start overnight and is the result of a many years of accumulated DNA damage.

Not sure I follow about living longer. By what you are saying, then, that would only apply for older populations. But the average age of melanoma discovery is 53. And many people you hear getting this cancer are in their 40's already. I personally know of one woman who had it in her early 40's. People in the past easily lived to that age. On a side note, I do not believe people died earlier in the past except for disease or injury (or maybe self-abuse that they did not know how to deal with, such as alcohol) skewing the stats. When I did my geneological studies, there were plenty of people who lived in their 70's, 80's and even 90's decades ago. Those who made it past the external dangers lived healthy into old age. So again, not sure how "living longer", even if it were true is a factor since a lot of these cancers happen in the younger population.

2) Environmental factors and nutrition definitely play a factor in many types of cancer, but the largest single contributor to skin cancer, specifically, is overexposure to UV radiation. This can be demonstrated not only in the lab, but by epidemiological data. We know that people who naturally have a high melanin content in their skin, such as blacks and other ethnic groups with darker skin, have very low prevalence of skin cancer. Fair skinned individuals that lack melanin have higher incidences of skin cancer. This isn't a problem in places like Northern Europe where the sun isn't harsh, but when these populations are transported to a different portion of the world their incidence of skin cancer increases. For example, Europeans that have immigrated to Australia or New Zealand, which lie along the equator and have extreme sun exposure, have much higher skin cancer incidences than their European counterparts--in fact, four times higher than in the US, UK, and Canada.

Again, I'm not really sure why that answers the question why more cancer now, and not in the past? People of previous generations had the same amount of UV from the sun. You're saying here about UV can be demonstrated in the lab to cause damage. OK --- suppose we had a time machine and went back and got some tissue (or even a person) from the past. Would that tissue react the same?

Processed foods and chemical exposure play a very small role in the development of skin cancer, but they are large contributors to other types of cancers. But that is for another discussion sine this thread is about skin cancer.

Not sure I agree with this at all. The skin is a system in the body, like the respiratory, the cardiovascular, skeletal, etc. They all work together and all get sick together. If processed foods affect some systems, it will filter into all. I'll use the veterinary doctor approach to this --- you can tell the health of the animal by its shiny coat (skin) and teeth. That's why horse traders looked at the horse's teeth. Someone with "sick skin" even if it could be "cured" will just get sick (cancerous) somewhere else.

 

[Claudya]

1) Age. People are living longer these days than in the past, and cancer is caused by genetic mutations that affect the cell's ability to regulate it's growth, causing them to proliferate uncontrollably. A longer life span means more mutations can accumulate over a lifetime, increasing the rate of cancer appearance in an aging population. Cancer doesn't start overnight and is the result of a many years of accumulated DNA damage.

That's a good point, but statistics show that even when look at the population aged <60 skin cancer rates have increased. I only found a German article about that which won't be of much use for you, but when I come home tonight I could search for English papers on skin cancer incidence.

Those who made it past the external dangers lived healthy into old age. So again, not sure how "living longer", even if it were true is a factor since a lot of these cancers happen in the younger population.

There might be a skew in that reasoning, too.
This is just a hypothesis, but I think a few decades back when life expectancy was lower those people that made it to 90 healthily were people of extraordinary health. The population of 85 and higher aged people 50 years ago and the population of 85+ year olds now might be totally different. It's possible that nowadays people can get to 80 and higher even though their cell repair mechanisms are damaged, thanks to modern medicine people can survive cancer at 70 and live until 95 (like my grandfather did), while 50 years back a person who got cancer at 70 was pretty much doomed to die from it. So what you have seen in your genealogy studies may be a sample of only the luckiest and healthies people surviving that long which is not representative for today's elderlies.

But I agree with you, more people reaching higher age may be a reason for a higher cancer incidence, but it's not the only reason.

Two things I think may play a role in skin cancer developement:
- we're exposed to more chemicals, processed food and unhealthy stuff than the generations past. That might cause an overall damage to our DNA and our cells, so people might get more likely to get various kinds of cancer (including skin cancer)
- the ozon layer of our planet that filters some of the sun's UV radiation has taken some damage from chemical air polution. I wonder if that's one reason for people getting more skin cancer now than in the decades past.

I also read that people are more likely to get skin cancer the closer they live to radio stations. So apparently VHF radio waves can cause cancer, too. >_<

 

[elizabethbraddock]

Not sure I follow about living longer. By what you are saying, then, that would only apply for older populations. But the average age of melanoma discovery is 53. And many people you hear getting this cancer are in their 40's already. I personally know of one woman who had it in her early 40's. People in the past easily lived to that age. On a side note, I do not believe people died earlier in the past except for disease or injury (or maybe self-abuse that they did not know how to deal with, such as alcohol) skewing the stats. When I did my geneological studies, there were plenty of people who lived in their 70's, 80's and even 90's decades ago. Those who made it past the external dangers lived healthy into old age. So again, not sure how "living longer", even if it were true is a factor since a lot of these cancers happen in the younger population.

Again, like I said, there are also environmental factors at play. For example, the amount of UV radiation that penetrates through the atmosphere has increased over the last three decades, and with it there is an increased incidence of skin cancer. Also, you are misrepresenting what I said about age and cancer; age and cancer are related as a general trend, and increasing age is related to increasing cancer incidence. Life spans were much shorter before the advent of modern medicine; the average life expectancy 200 years ago was less than 40, and the average life expectancy in the US in the early 1900's was 50. This is an average, and there will always be people who live longer or less than the average.

Not sure I agree with this at all. The skin is a system in the body, like the respiratory, the cardiovascular, skeletal, etc. They all work together and all get sick together. If processed foods affect some systems, it will filter into all. I'll use the veterinary doctor approach to this --- you can tell the health of the animal by its shiny coat (skin) and teeth. That's why horse traders looked at the horse's teeth. Someone with "sick skin" even if it could be "cured" will just get sick (cancerous) somewhere else.

Again, you are misrepresenting what I wrote. The environment and nutrition do play a role in the development of cancer to varying degrees, and it depends on the cancer type. Nutrition and environmental exposure plays a large role in the development of stomach and colorectal cancer, for example. There is a complex interaction between the body and exogenous carcinogens, and genetic factors also come into play. I did not say that the environment and chemical exposure does not contribute to skin cancer, but that the major cause of skin cancer in a majority of skin cancer cases is UV exposure; therefore, chemical and nutritional intake is only a minor contributor to skin cancer. They may play larger roles in other cancer types, but it is not the major contributor in skin cancer.

The development of cancer is not simple and there is not a singular cause, it takes many years to develop the mutations necessary to induce tumorigenic growth. There are several biochemical pathways that must be disrupted before a cell becomes cancerous.