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The real way to prevent cancer

Long, long ago, seemingly in a galaxy far, far away, I first encountered quackery on the Internet. Because I am a cancer surgeon, naturally I gravitated towards cancer quackery at first. Believe it or not, it was quite some time after that before I started to take an interest in what has become a major focus of this blog, the antivaccine movement and the misinformation it spreads. Both are equally damaging in their own way. True, these were back in the deep, dark days when I used to cruise various Usenet newsgroups, ranging from alt.revisionism (Holocaust denial), sci.skeptic (of course!), and misc.health.alternative, where I cut my teeth looking at pesudoscientific and antiscientific health claims. By the time I started blogging I had become all too acquainted with antivaccine wingnuttery.

Even way back then, if there was one thing I learned about aficionados of alt-med, it’s that they have a near mystical belief in the power of diet and other lifestyle interventionsn to cure all ills. In fact, when it comes to cancer, it’s not uncommon to find claims that it is possible to prevent almost all cancer. Typically, the argument in essence boils down to denialism of genetics. In other words, some of the more radical proponents claiming that we can virtually totally control whether we get cancer or not will gloat about how the “genetic trail hasn’t led to a cure” and that genetics accounts for far fewer cancers than previously thought. They will seize on studies from the relatively new field of epigenetics as evidence that nearly all cancer is caused by environmental influences. The statement is, of course, that we can control our health. The implication underlying that statement and assumption is that if someone is not healthy it is his fault. As I’ve said, it’s the Law of Attraction, in which intent is all; i.e., wishing makes it so. Often reasonable cancer-preventing strategies based in science are heavily leavened with woo and quackery.

The magical thinking of many alt-med mavens aside, however, it is true that a significant number of cancers could be prevented by lifestyle modifications. Conventional medicine recognizes this and has long recognized this. The number is not insubstantial, either. Again, conventional medicine has recognized this. However, realizing the power of prevention of cancer does not require a raw vegan diet, a boatload of supplements, or invoking magical mystical universal energies. Conventional medicine tells us that it takes a few simple things, and the incidence of cancer could be cut by as much as 50%. Indeed, a report on the Union for International Cancer Control (UICC) World Cancer Congress 2012 tells us so:

More than 50% of cancer could be prevented if people simply implemented what is already known about cancer prevention, according to a researcher here at the Union for International Cancer Control (UICC) World Cancer Congress 2012.

Graham Colditz, PD, DrPH, from the Washington University School of Medicine in St. Louis, Missouri, reported that a number of interventions, largely involving lifestyle behaviors, but also involving higher-cost interventions in high-income countries, could prevent a large proportion of cancers in 15 to 20 years if widely applied.

So what is already known about cancer prevention? The “biggest buy” would come from a simple intervention that virtually all of us know about. That’s not to say it would be easy. Far from it. But it is simple: Get more people to stop smoking. One-third of cancer cases in developed countries can be attributed to smoking. It’s just that bad. Colditz points out that it is possible to reduce smoking-related cancers dramatically:

“One third of cancer in high-income countries is caused by smoking,” Dr. Colditz said. If smoking rates could be reduced to the current levels in Utah [about 11%], the United States could see a 75% reduction in smoking-related cancers in 10 to 20 years — a target that Dr. Colditz feels is feasible in countries where smoking rates have already declined considerably.

Unfortunately, the number of people in the rest of the US who smoke is nearly twice that percentage; so this is not an easy task. Tobacco control efforts have floundered upon the rocks of human nature time and time again. It’s one of those things that easy to say but oh-so-hard to do.

Here’s another thing that’s equally hard to do:

Similarly, it is estimated that being overweight or obese causes approximately 20% of cancer today. If people could maintain a healthy body mass index (BMI), the incidence of cancer could be reduced by approximately 50% in 2 to 20 years. (A healthy BMI for cancer prevention is from 21 to 23 kg/m², as other speakers pointed out.)

Which is, of course, related to this:

Dr. Colditz, among others, estimates that poor diet and lack of exercise are each associated with about 5% of all cancers. Improvement in diet could reduce cancer incidence by 50% and increases in physical activity could reduce cancer incidence by as much as 85% in 5 to 20 years.

I must admit that I was a bit confused by this paragraph. If poor diet and lack of exercise are assocaited with about 5% of all cancers, how could improvement in diet reduce cancer incidence by 50% and increases in physical activity could reduce cancer incidence by 85%? I assume that what is meant is that improvements in diet would reduce cancer incidence by 50% within those 5% of cancers associated with diet and that increased physical exercise could decrease cancer incidence by 85% within the 5% of cancers associated with a sedentary lifestyle. Otherwise, all the percentages start adding up to more than 100%. Be that as it may, it should be noted that, contrary to the rants of alt-med enthusiasts, science-based medicine doesn’t deny that alterations in diet and lifestyle can reduce the incidence of cancer. What alt-med enthusiasts don’t like is that the data don’t support their claims; the true effect of these interventions on cancer is not as potent as they believe (and would have you believe). That’s not at all to say it’s not worth it to correct these problems. After all, obesity, poor diet, and sedentary lifestyles are associated with more than just cancer. They’re associated with cardiovascular disease and type II diabetes as well.

Under science-based medicine, there are many reasons to do these things, both at the population and individual level. At the population level, doing these things would definitely impact the incidence of cancer. At the individual level, doing these things make people healthier and less prone to a wide variety of diseases.

Of course, what amuses me most about this article is the rest of the science-based interventions that would decrease the incidence of cancer. I’ll give you a hint.

Just a little hint.

Keep scrolling down a little more.

It’s really going to shock you.

It involves…vaccines! Yes, vaccines:

Eradicating the main viruses associated with cancer worldwide by implementing widespread infant and childhood immunization programs targeting 3 viruses — human papillomavirus and hepatitis B and C — could lead to a 100% reduction in viral-related cancer incidence in 20 to 40 years, he added.

And the dreaded pharmaceuticals:

Then there are the “higher tech” interventions that, at least in high-income countries, could prevent a significant proportion of cancer and cancer-related mortality, starting with breast cancer.

“We have shown that tamoxifen reduces the rate of both invasive and noninvasive breast cancer by 50% or more, compared with placebo, at 5 years,” Dr. Colditz said.

And more pharmaceuticals and—gasp!—screening:

In addition, Dr. Colditz noted that approximately 20 years of follow-up has shown that aspirin is associated with a 40% reduction in mortality from colon cancer. Screening for colorectal cancer has a similar magnitude of mortality reduction (30% to 40%).

So what is the real way, as opposed to the fantasy way, to prevent cancer? It’s simple (although not easy). Don’t smoke. Lose weight. Exercise. Eat a healthy diet (and, no, that diet doesn’t have to be a raw vegan diet, as some would have you believe). Get your vaccines. Get screened for certain diseases. If you’re at a high risk for cancer, use science-based regimens that might involve taking, yes, pharmaceutical products to reduce your risk.

Because, in the end, cancer is complicated. It’s not a single disease. In fact, individual cancers can be argued not to be single diseases in that they exhibit incredible heterogeneity within individual tumors. So is preventing cancer.

By Orac

Orac is the nom de blog of a humble surgeon/scientist who has an ego just big enough to delude himself that someone, somewhere might actually give a rodent's posterior about his copious verbal meanderings, but just barely small enough to admit to himself that few probably will. That surgeon is otherwise known as David Gorski.

That this particular surgeon has chosen his nom de blog based on a rather cranky and arrogant computer shaped like a clear box of blinking lights that he originally encountered when he became a fan of a 35 year old British SF television show whose special effects were renowned for their BBC/Doctor Who-style low budget look, but whose stories nonetheless resulted in some of the best, most innovative science fiction ever televised, should tell you nearly all that you need to know about Orac. (That, and the length of the preceding sentence.)

DISCLAIMER:: The various written meanderings here are the opinions of Orac and Orac alone, written on his own time. They should never be construed as representing the opinions of any other person or entity, especially Orac's cancer center, department of surgery, medical school, or university. Also note that Orac is nonpartisan; he is more than willing to criticize the statements of anyone, regardless of of political leanings, if that anyone advocates pseudoscience or quackery. Finally, medical commentary is not to be construed in any way as medical advice.

To contact Orac: [email protected]

32 replies on “The real way to prevent cancer”

A question: since many types of cancer have a genetic base, it would be useful to keep a look at your relatives, and your grandparents and grand-uncles/aunts, as well, correct?

It boggles my mind that when a proper doc tells you to stop smoking or change your diet a little bit you don’t do it. If a fake tells you the same thing, you do. And tell everybody how magical and wonderful it is.

I get this a lot during lunch and learn presentations. If the topic is vegan and vegetarian diets, without fail, ALWAYS, someone in the audience will hog the Q&A at the end and turn it into a debate about how being vegan makes one disease-proof. Unfortunately, I can’t dismiss this when it’s obvious others in the group share this belief. It has to be addressed and I wonder to what extent the Q&A ends up overshadowing my initial presentation.

On an unrelated note, I was once told I’m not open minded enough, during a discussion about micronutrients, when someone blew me away with: “Dr. Mercola says staring at the Sun in the late afternoon is the best way to get your vitamin D”. I may have visibly cringed at the Dr. Mercola part, or maybe it was my eye twitching Chief Inspector Dreyfus style. I don’t know. Something gave me away as a Mercola denier. Happily, the whole group looked puzzled by this bit of insane advice. Later, I overheard the person who brought this up mumble something about Dr. Mercola being a doctor and as such having more credence than someone like me (I have a MSc in nutrition). I get some Dr. Oz pearls every now and then, but mostly, the weirdest ones come from Mercolites.

Also, I recently overheard a woman talk about how cancer runs in her family, but she won’t get it because she works very hard at thinking positive thoughts – according to her recollection, neuroscientists on the Larry King show said the brain can heal anything.

Sigh…

Recently, Internet Radio Impressario Gary Null addressed** the issue of viruses that cause cancer- of course he veered off into ‘prevention’ through veganism, supplement-loading, exercise and spirituality ENTIRELY avoiding the role vaccines play in prevention.
I found this odd.

@ Marina:

various vegan ‘pearls’ are tossed @ Gary Null.com and the Progressive Radio Network.com including a 3- part series on the topic. His argument involves twisting data into Celtic knots and Mobius rings to arrive at the conclusion that diet is most important in preventing cancer; usually he discusses third world countries diets that limit animal products, neglecting the fact that cancer occurs everywhere.

** if anyone is interested in the broadcasts, I can probably dig it at least one in the PRN archives

Indeed, cancer occurs everywhere. I like to point out that it is also found among wild animals, which, as far as I can tell, eat species-specific diets and get plenty of exercise.

I’m most annoyed by so-called “superfoods” and “quick-fix” dietary interventions that are supposed to boost this, or eradicate that, and for which there is zero or, in some cases, contradicting evidence that they work. My pet peeve is the detox plan in its seemingly endless variety of forms of which I find the “cancer detox plan” to be the most misleading (they all are, but that one really gets under my skin primarily because it involves people facing death).

There’s also cancer fighting juicing don’t you know (because removing all the pulp/fiber from your fruits and vegetables is a grand idea).

When patients first visit a general practitioner or a specialist, there is always a “family history” section to check off for various diseases/disorders that are sometimes genetically-linked:

http://www.cdc.gov/genomics/gtesting/ACCE/FBR/index.htm

There are hundreds, if not thousands of these genetically-linked diseases/disorders or “conditions”. Some of these “conditions” do not impact a person’s health such as male pattern baldness or the type of ear wax that you secrete:

https://www.23andme.com/health/Earwax-Type/

The “family history” section is (do’h), on the patient’s history form that is provided to each new patient.

usually he discusses third world countries diets that limit animal products

Ah, does he look at a third-world population that limits animal products and, due to its third-world lack of adequate health care and sanitation, has lower incidences of age-related cancers (due to people not living as long), and claim the limitation of animal products reduces cancer?

I’m a vegetarian for multuple reasons, and I very much hate bullshit justifications for being a veggie, as they make me look bad. :p

@Ren

You just had to throw Gangnam Style in there, didn’t you? Ever since my friend and a few others danced that at his wedding, I’ve been seeing it everywhere and can’t get the song out of my head! I approach elevators with a certain trepidation, too.

@Todd – My wife’s cousin is getting married in two weeks, and her brother and I will recreate the elevator scene at the reception. I’m getting a tux and all.

@Lilady – It happens to all of us. I remember my first crisis of faith. I’m sure he just needs more rest and time to write.

@ Ren: I don’t know how all the science bloggers “do it”, in spite of having day jobs (or multiple day jobs) and a social life.

P.S. Could you provide some details about the wedding reception (date, time, when, where)? 🙂

@Ren

I also expect you to recreate the LMFAO video “I’m Sexy and I Know It”. Video, of course, will be a necessary submission for this month’s Shills and Minions paycheck.

Gary C — well, skin cancer is another one where there are simple ways to greatly reduce the risk. Number one is to avoid getting sunburns, and don’t get into cosmetic tanning. It’s awfully hard to completely avoid the Sun, though, especially since we depend on it for production of Vitamin D.

Mary Sue — yeah; my daughter got classed as “obese” by her BMI, but you could see every muscle under her skin. She was just very solidly built for a two-year-old. (She has since lengthened out considerably, and is now a little on the light side in terms of BMI — but you can tell by looking at her that she’s not really underweight. She’s just gone from solid as a rock to a beanpole, which apparently is common in her dad’s family — he’s certainly got the beanpole frame.)

So my question is how does a 20 year old get kidney cancer who has had all these shots, weighs 150 pounds, eats an organic mostly veggie diet (ocean fish and range chick) and has never smoked?? a disease more inclined for a 60+ person

It’s odd how some people are more afraid of a sausage than a cigarette, health-wise (I was a vegetarian for several years for ethical reasons but took up meat again for health reasons). I once knew a vegan who smoked, and appeared to live on potato chips and beer. He’s still alive, surprisingly, last I heard.

I read recently that half of all habitual smokers will die of a smoking-related disease. Half. Those are not good odds for a habit that has nothing positive about it at all, except that it wards off the discomfort of withdrawal. I quit nearly 9 years ago and regard my younger self as insane for ever taking up such a stupid habit.

@ Roaderstergal:

Exactly: they leave out the part about shorter life spans and death from other causes. They also claim a lower rate of CV disease- sure, because they don’t live long enough (I know that high meat / fat consumption isn’t great either). Because of my ex’s interesting vocation, I had the dubious pleasure of visiting a few tropical ‘paradises’ that weren’t exactly paradisal.

@ Gary C:
@ Calli:

The fact remains that woo-meisters push sun exposure AND also pooh pooh sunscreens/ sunblocks: I have heard this many times, including from the ‘usual suspects’.Terrible! Some even go as far as to say that vitamin D from sun exposure *combats* cancer so it should be increased- *without sunscreeens*.

Many of my relatives are extremely white: several years ago, my cousin, a handsome fair haired businessman, found that he had melanoma – he’s now alright but has had painful surgery and treatments. My good friend had a small basal cell carcinoma removed from the side of her nose: the surgery was complicated by the fact that it was near her eye. Although my cousin is half Irish and my friend 100%- ANYONE can get skin cancer. Some die ( e.g. Bob Marley)

I avoid the sun since age 18: I’ve never had a tan but have had a burnt nose a few times. .

@ Krebiozen:

Unfortunately, many young ( and some older) fashion-conscious women ( and a few men) use cigarettes as an appetite suppressant and meal substitute.
As the fashionistas often say:”It’s to die for”.

@Gail

“does a 20 year old get kidney cancer who has had all these shots,”

“….all these….”

Perhaps he s/he caught malignant language dysfunction from you?

@Gail — just nuts, isn’t it? Some cancers just have no apparent cause, a certain amount of randomness always.

A good friend of mine was just found to have a malignant tumor in his cerebellum (I don’t know exactly which type); surgery was attempted but they were only able to remove 30% of it. Luckily he’s not prone to woo. I’m not casting around for a reason, these things just happen.

a href=”http://www.nytimes.com/2012/09/06 science/far-from-junk-dna-dark-matter-proves-crucial-to-health.html?_r=1&ref=health”>The Encode Project certainly gives validation to the idea that epigenetics could be a focal point for future cancer research. Science is starting to show how gene switches can be influenced by environmental, dietary, and yes, nutritional factors:

Links Between Nutrients, Genes and Cancer Spread Documented

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