Respectful Insolence

Cancer and “fate”

Last week, our Seed overlords published on the flagship an Agence France-Presse article about a survey in Britain whose results showed that large numbers of people believe that cancer is due to “fate” rather than risk factors that can be modified to decrease one’s risk of developing the disease:

LONDON (AFP)–More than a quarter of people believe that fate alone will determine whether they get cancer, not their lifestyle choices, according to a survey conducted by charity Cancer Research UK.

The poll of more than 4,000 adults across the country asked people if they thought they could reduce their risk of getting cancer or whether it was out of their hands.

A total of 27 percent of people said cancer was down to fate, with more women than men believing cancer was a matter of destiny than prevention through measures such as quitting smoking or eating healthily.

Among those from the most deprived areas, the figure rose to 43 percent but fell to 14 percent in the most privileged areas.

The survey also found that smokers were 50 percent more likely than non-smokers to believe that getting cancer was the luck of the draw.

Cancer Research UK’s director of cancer information, Dr Lesley Walker, described the results as “worrying”.

She added: “It is alarming that such a large percentage of the British population do not realise that half of all cases of cancer can be prevented by lifestyle changes.

A number of other bloggers have looked at this study and concluded that it means that the British people who reported this are stupid, “really dumb,” or the result of bad education. Even fellow ScienceBlogger Tara piled on a bit.

I beg to differ; none of this is unexpected, and bloggers are reading more into this survey than is warranted. (It’s painfully obvious that none of them have ever actually tried to explain to a patient how such risk factors apply to them personally.) Leave it to a medical student at Over My Med Body to get much closer to the correct interpretation:

If you look at groups of people, you can easily say that smoking increases your risk of many, many cancers. And other lifestyle choices definitely increase your risk of cancer. But look what I said–increased risk. Not guarantee. Not all smokers develop lung cancer, not all smokers develop emphysema. Not all obese people develop diabetes, and not all people who develop diabetes are obese.

You can say that X increases your risk of cancer by 99%, but when you go down to the individual level, that individual has to either develop cancer or NOT develop cancer. We can’t say which smokers will get cancer and which won’t, only that they’re more likely to. There’s still random chance–if you want to call it fate, so be it–that gives people cancer.

So there you are, Brits, you’re right.

If you want to reduce your risk of cancer, heart disease, and other big killers, prevention is the key, and lifestyle changes can do a lot. But we want to accurate for the individual, we don’t know who will get cancer.

Indeed. Translating epidemiological evidence and risk factors into predictions about whether any single patient will get cancer is fraught with difficulty. It’s all probabilities, and we can never tell any single patient whether they will or will not get cancer with much certainty. For example, take what is probably the strongest and certainly most universally recognized common risk factor for lung cancer, smoking. After 50 years, only around 25% of heavy smokers will develop lung cancer. For shorter periods of smoking or less heavy smoking, the risk, although substantial, is even less than that. Granted, heavy smokers have at least a ten times higher risk of lung cancer than nonsmokers, but it still means that most smokers will not get lung cancer during their lifetimes. In that way, “fate,” if by “fate” you mean random chance,” plays a large role. Just how difficult it is to produce prognostic factors that can be used to give a good estimate of individual risk is shown in a large study published in the New England Journal of Medicine last month.

I once cited a very good New York Times article about how difficult it is to convince patients that such risks apply to them. I will cite it again. In it, the Dr. Abigail Zuker is trying to get her mother to exercise a bit, trying to cite studies showing how moderate exercise has health benefits in the elderly, but her mother would have none of it:

Studies,” she says, dripping scorn. “Don’t give me studies. Look at Tee. Look at all the exercise she did. She never stopped exercising. Look what happened to her.”

End of discussion. Tee, her old friend and contemporary, took physical fitness seriously, and wound up bedbound in a nursing home, felled by osteoporosis and strokes, while my mother, who has not broken a sweat in the last 60 years, still totters around on ever-thinning pins. So much for exercise. So much for studies. So much for modern clinical medicine, based on the randomized allocation of treatment and placebo. All that beautiful science, stymied by the single, incontrovertible, inescapable image of Tee, the one who exercised but grew hunched and crippled anyway.

Is Dr. Zuker’s mother “stupid” or “ignorant”? Not from her perspective, and indeed it can all be viewed as a difference in perspective conveyed by this excellent metaphor:

It is medicine’s eternal quest, these days, to sell impressive science to unimpressed patients, and it is hard to think of a group less equipped to do it than doctors. Doctors are specifically trained not to think like normal people, not to see what others see or to reason as others reason. They — er, we — come to operate in an atmosphere so thin, so heady and attenuated with the power of statistical analysis, that one might wonder whether we are really on the same planet as the patients we try to convince of our truths.

“Exercise helps the elderly.” The doctor sees, from a perch suspended somewhere up in the sky, a large football field filled with the elderly. There are thousands of them down there, all dressed in sweats and sneakers, dumbbells at their feet. Half of them are using the dumbbells, or are down on their backs, doing leg lifts. The others just stand around.

Over the years, of course, the ranks thin. The doctor watches, counts. It begins to look as if there are more exercisers left. After decades, there are definitely more exercisers. Of course, there are still a few sloths standing around (and one of them looks suspiciously like my mother). But by and large, the exercisers come to rule the field.

That is the view from on high. Down on the field, of course, the view is quite different. You are standing in a thick crowd, minding your own business, living your life, but you cannot help noting that the man over there threw his back out with all that exercise, and the woman next to you, grunting to lift her dumbbell, had a heart attack. You cannot see to the other end of the field and have no idea what is happening there. But watching all the sweating and grunting and seeing some of those exercisers disappear anyway, you decide to opt out.

You could say the same thing about smoking, drinking, eating fatty food, or whatever risk factor for whatever disease you would like to think of. On the ground, dismissing scientifically demonstrated risk factors for disease may not seem so irrational, and it’s easy to forget that and attribute such resistance to scientific knowledge as being due to ignorance, stupidity, or just plain stubbornness. Indeed, the weaker the risk factor, the more difficult it is to appreciate its danger “o nthe ground.” Smoking increases your risk of premature death by ten-fold or more, and yet everyone still knows examples of smokers who lived to a ripe old age and health freaks who keeled over dead at age 50. On the ground, even for smokers, it can appear that who lives and dies and who gets cancer or doesn’t are largely due to “fate,” particularly if a bit of denial is at work helping people to ignore inconvenient warnings from their doctor or their public health officials that certain unhealthy activities and lifestyles that they enjoy and don’t want to change are unhealthy.

Only people who have never tried to convince patients to change such lifestyles for the benefit of their health would so blithely attribute this belief in “fate” to stupidity or ignorance. In some cases it may be stupidity or ignorance, but in the majority of cases it probably is not. For instance, 90% of the people in the U.K survey knew that smoking increased the odds of developing cancer, and that still didn’t stop a significant proportion from attributing whether smokers get cancer or not to “fate.” It’s all easy from the air to dismiss patients as being “ignorant” or “stupid,” but it won’t help to persuade them that there are indeed actions that they can take themselves to decrease their risk of developing cancer.

Comments

  1. #1 Graham
    January 8, 2007

    Really flattered that you agreed with me, Orac! I really respect your opinion as a physician and Knower of The Literature.

  2. #2 TW
    January 8, 2007

    Thank you for a well written post.

  3. #3 Koray
    January 8, 2007

    I think it is one of the known fallacies to prefer stories over statistics (I haven’t read it, but it’s described in here: http://www.amazon.com/Dont-Believe-Everything-You-Think/dp/1591024080)

  4. #4 Interrobang
    January 8, 2007

    I think it basically comes down to most people being crap at risk assessment. It’s the Availability Heuristic in action. People are more afraid of big, loud, uncommon risks than small, quiet, commonplace risks. Who doesn’t know someone who’s had cancer? On the other hand, buttonhole any random hundred people off the street and ask them whether flying is safer than driving, and a significant majority of them will tell you the wrong answer, in large part because when a plane crashes (a big, loud, infrequent risk), lots of people usually die, and it makes the news. Car accidents, not so much. We’ve come a long way from the world of The Great Gatsby.

  5. #5 Ethan Romero
    January 8, 2007

    Hey Orac, I don’t interact with patients but I am familiar with the difficulties of explaining how risk is calculated and what it means to individuals and populations. Do you think that the component cause model (sometimes called Rothman’s component cause model) could be a useful framework for explaining individual-level “risk”? You might be able to explain that smoking “completes” many of the causal mechanism leading to [whichever] cancer in the individual. The change in risk due to smoking could then be explained as something like the difference in buying one lottery ticket (e.g. the causal mechanism whose only component is genetics) to buying 10,000 tickets (e.g. all the pathways that include smoking such as (smoking, genetics, infection) or (smoking, diet, genetics) etc…).

    It makes sense to me, but I have been a graduate student for, ugh…too long, so I’m certainly not qualified to comment on, well, much of anything except my minutiae (which is getting both relatively and absolutely smaller and smaller by the day).

  6. #6 David Harmon
    January 8, 2007

    ?!: “I think it basically comes down to most people being crap at risk assessment.”

    At most half right — the other half being that people do not normally arrange their lives with much effort toward maximizing their lifespans. Normal human planning is much shorter-term than that, and people have many more immediate concerns than extending their lifespan at the far end. And then too, a true calculation of the various risks would depend on individual genetic variations, often subtle or untestable.

    The Norse peoples spoke of a sort of individual fate, called “weird” — the catchphrase being that “no man may escape his weird”. Strangly enough, that makes some sense when viewed in the light of modern psychology, development, and genetics.

  7. #7 Renee
    January 8, 2007

    I think it was unfortunate that the original question in the survery used the word ‘fate’, as if it is a person’s destiny to get cancer. I think the word ‘chance’ would have been a better choice.

    The grand majority of people do not read cancer research or epidemiology journals. They don’t read Science nor Nature. The grand majority of people’ perspectives about cancer is what they observe directly regarding the experiences of their relatives, friends and co-workers. And frankly, from any one individual’s perspective, there does not appear to be noticeable reasons why certain people they know develop cancer, and others with the same health habits don’t (beyond the obvious one of smoking). People observe all the time that decent, healthy people get this disease.

    Several years ago, when Linda McCartney (the first wife of Paul McCartney) died in her mid-50′s from breast cancer, there was some consternation about this. McCartney was a vegetarian, and people couldn’t understand how someone so health-conscience (sp?) could die from cancer so young.

  8. #8 wrg
    January 9, 2007

    “It is medicine’s eternal quest, these days, to sell impressive science to unimpressed patients, and it is hard to think of a group less equipped to do it than doctors.”
    I suppose it’s intentionally so, but I find that claim quite hyperbolic. I should expect that those in any career outside of medical science would be less equipped. She seems to follow up by suggesting that doctors do not succeed in explaining science because they think scientifically. Frankly, I find this bizarre. Do we want to hire priests and dowsers to talk to patients, instead? They surely won’t be hindered by too many scientific thoughts.

    I haven’t given the matter long thought, but I’d be more inclined to suspect that the problem is that science isn’t taken seriously enough. The traditional image of Science as a mysterious practice conducted by white-coated figures in secluded laboratories doesn’t help. Science, of course, is really just basing ideas on observation and trying hard not to fool oneself. Should doctors fool themselves more, so as to relate to patients better?

    Seriously, though, what would Dr. Zuker have doctors do? All that occurs to me would be to follow the tradition of great skeptical speakers to persuade patients that “other ways of knowing” mostly consist of other ways to fool oneself, but it’s unclear that doctors have the time or patients the inclination to follow such a program. Failing that, what can you do but to present the science honestly and try your best to convince patients that it means something?

  9. #9 Crosius
    January 9, 2007

    The simplest explanation is rationalization. If it’s a mater of”fate” or chance, the smoker, overeater, etc. has no reason to change their habits (and most of them like/enjoy/are hokked on their present habits).

    Never underestimate the power of the mind to practice self-deception.

  10. #10 Thinker
    January 9, 2007

    Certainly, doing science (including ,in this case, also applying science in the form of medicine) and communicating science are activities that require different skill sets.

    While there is nothing to prevent good communicators from choosing science as a career, science education in general doesn’t do much to develop communication skills, and when there is some training, it is usually aimed at improving communication within the scientific community (writing better papers, giving better talks etc.) rather than how to get a scientific message across to the lay person.

    This particular case, communicating about risk, actually parallels the one about alternative therapies. From the perspective of the individual, it is so easy to say: “I don’t care what your randomised double-blind studies say – Wendy feels much better after her homeopathy treatment, so that’s the truth to me!”

    (This from someone whose significant woman both smokes, albeit very little, and believes in homeopathy to a degree. None of my explaining about how we reach rational conclusions about those things have affected her opinions very much. After five years of trying to communicate this in different ways but not succeeding, a completely rational person would of course say that this nutcase isn’t worth the trouble and give up, either the convincing or the relationship. However, even those of with a science background aren’t completely rational about everything…)

  11. #11 Dunc
    January 9, 2007

    Never underestimate the power of the mind to practice self-deception.

    Indeed – or the power of addiction to mess with your ability to make rational decisions. And I say that as a smoker with no intention of quitting. I know it’s irrational, but the psychology of addiction is such that I’d rather be irrational than change a fundamental aspect of my thinking.

    Another thing that occurred to me about this study is that genetic predisposition appears to be a factor in many cancers – you could call that “fate” and not be too far wrong.

  12. #12 potentilla
    January 9, 2007

    Furthermore, this was a survey, not actual science, and all we know about it, as far as I can find out, is from the press release, which as you will see, Agence France-Presse has basicaly copied out. We can’t actually tell what questions were asked of whom; let’s hope it was a bit more scientific than the bottom left-hand corner of the home page of Cancer Research UK suggests.

    In fact, as far as I can tell from the press release archive, this survey was done more than a year ago – see press release in Jan 06 on the subject – and the new release was just intended as a reminder about their Reduce the Risk campaign.

  13. #13 Christina
    January 10, 2007

    Renee- Ha! Vegetarians = health conscious. If only that were true. Another fallacy. My boyfriend and I are both vegetarian and you’ll still find us stuffing our faces in front of the tv most nights. When I’m fifty and I keel over I’ll probably still find that hilarious.

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