Is surgery a placebo?

April 10, 2007

From Martin Hutchison in BBC News:

In the early days of medicine, physicians might diagnose patients using bumps on their head, or dispense a couple of leeches to draw off “ill humours”.
Yet a medieval doctor might give a more confident response than his modern equivalent if a patient asked for the evidence to support their treatment.
These days, it seems many of our “tried and tested” approaches to disease are nothing of the kind.

Researchers writing recently in the British Journal of Surgery concluded the practice of daubing patients with a disinfectant skin gel prior to operations made little or no difference to the rate of infections they suffered afterwards. Simple soap and water was just as effective.

However, despite this, it’s more than likely that, in future, waking up after your operation in many British hospitals, you’ll have that tell-tale orange stain around your wound. You’ll have been given a treatment that doesn’t work.

Read more here. The article goes on to describe a study by Andrew Booth at the School of Health and Related Research in Sheffield that found that 15-20% of health care facilities in Britain used treatments that “did not have a shred of worthwhile evidence to support their use.” There are of course, many unfortunate consequences of this. The first is that patients often aren’t getting the treatment that they need. Second some of the ill-informed treatments are actually harmful. One example mentioned by the piece is the test for prostate specific antigen (PSA) which is done as a screening test for prostate cancer despite the fact that those who have the test performed are just as likely to die from prostate cancer as though who don’t. Moreover the use of the test may end causing someone to have an unnecessary surgery performed.

This last issue, unnecessary surgery, made me wonder. Just how scientific are surgeries in general? After all it’s not so easy to give someone the sugar-pill equivalent of a surgery to really “subtract out” the placebo effect in the standard double-blind fashion. To really test the efficacy of a given surgical procedure you’d have to give some group of people a scar and tell them you’ve actually performed the surgery, and since this enters an ethically gray area (to say the least), it hasn’t to my knowledge, been done. Furthermore if the placebo effect really does have something to do with “the power of suggestion” then one would expect the placebo effect to be extremely high in the case of surgeries since one is literally removing a tumor or repairing a malfunctioning organ, in a very dramatic and immediate fashion. In fact, saline injections are very useful in burn victims when they are told that they’re being given a very strong painkiller. So the invaseiveness of a procedure seems to increase the placebo effect. Another important factor is the niceness of the doctor prescribing the treatment, which also increases the effect of the placebo.

So sometimes placebos are useful. But not all of the time of course. A Danish study of placebos found that 48% of general practitioners had prescribed a placebo in the last year. The placebo prescriptions range from vitamins for fatigue, to antibiotics for viral infections (even though antibiotics only kill bacteria, not viruses) which is certainly not a good thing since natural selection will give rise to ever nastier antibiotic resistant super-bacteria! So I’m more or less on the pro-placebo side of the debate, but only if those Danish doctors switch to a more inert placebo for viral infections. So Danes, if you’re reading, here are some suggestions for harmless placebos: vitamins(!), eat more vegetables, vote for Bill Richardson for President, comment on ..dotted and undotted dotterings.., and of course more ice cream from Scoops!

I tend to view science in terms of the larger cultural context of human institutions. As I wrote in an earlier post, I think culture is best understood as a complex network of symbols. I’m not pretending that this is an especially unique perspective, since it’s largely borrowed from the preeminent cultural anthropologist of the late 20th century, Clifford Geertz, who, incidentally borrowed it from Max Weber. For example, Weber was famous for saying that man was caught in “webs of significance that he himself has spun.” Symbols are, in a sense, the units out of which culture is built. Viewing culture as symbol is nice, because it encompases an important aspect of human interaction: it is fundamentally interpretational. Is my wink an indication of a secret understanding between the two of us, or is it a half-joking bursleque wink? Or am I pretending it to be a half-joking burlesque wink? As Geertz himself put it, culture is a series of “winks, upon winks, upon winks!” Symbols, and subsequently culture, are contested territories of meaning. The realm of the beaten path of meanings constitutes the mainstream of a given culture. Why do we as a species gravitate to a unified, shared system of meanings? Well the honest answer is, yeah right! no one knows. A more exciting, and therefore probably wrong answer, is that we strive for consistency of intepretation because it simplifies matters. The behavior of humans, to far higher degree than probably any other animal, are not as dependent on their genes. When we are faced with a difficult decision, be it behavorial or interpretational, we filter it through a culural complex of meaning to arrive at the conclusion.

Now what does this have to do with good ol’ hard-nosed science? Science, it is (perhaps) often said, is above the relatively banal matters of culture. In it’s most arrogant formulation it is said that science is trans-cultural. Poppycock. Science is another cultural system in just the sense discussed above. True, science does cherish falsifiability and predictability, but these are just particular ideals that a subculture of Western civilization has chosen to venerate, albeit ideals that I happen to enjoy. That being said, science is indeed unique as a cultural form. It has enjoyed unparalleled success in its application to technological improvement and the expansion of a falsifiable system of knowledge. Certainly, all cultures are dynamic, ever-changing institutions, but only in science I think is change the name of the game. As far as I know, science is the only cultural form to paradoxically, institutionalize revolution. This leads to what I’d offer as the natural definition of science (see the earlier post on definitions too):

A particular cultural form which has uniquely institutionalized revolution. The status of these revolutions are formalized by experimental confirmation of a parsimonious theory.

In science, all knowledge is built on sand, and the whole goal is knock down the previously exisiting sand castle and build one that’s more stable!

I know definitions usually come at the beginning rather than the end, but hey, every exit is an entrance and versa vice, right?

Astrobiological musings

March 27, 2007

I was fairly astounded to find that astrobiology – the study of whether life exists elsewhere in the universe – is actually a respected field of study in academia. At its heart astrobiology is quite speculative, since we only have one notable data point of evidence that life occurs at all in the universe, namely good ol’ Mama Earth. There is however, a useful rule of thumb often attributed to Richard Feynman (who is incidentally also credited with a good portion of modern physics), that whatever is not forbidden in nature is mandatory. That is to say, if nature allows for the existence of self-replicating molecular systems on one rock around a fairly average star, then its not unreasonable to think life might exist elsewhere. The case for the commonality of life is strengthened further by the relatively recent discovery of so-called “extremophiles” thriving in the least likely of places on Earth: boiling water surrounding hydrothermal vents, underneath permafrost, and inside rocks to name just a few. Here’s an example of a particular extremophile.

A Pompeii worm colony near a hydrothermal vent.

This is a Pompeii worm colony near a hydrothermal vent. Needless to say, the existence of such extreme forms of life greatly reduces the number of necessary environmental criteria for life. Thus microbial life at least might very well be quite common in the universe.

In fact we might not need to look beyond our own solar system for other forms of life. Our very own Europa (one of Jupiter’s 63 moons!) might not only have liquid water beneath its icy surface but also have a significant heat source. That whole source of heat thing is not irrelevant when you consider that at Jupiter’s orbital distance the luminosity of the Sun isn’t that much greater than the background stars. The source of heat is unknown at the moment, but an intriguing possibility is the strong gravitational tidal flexing Jupiter’s large mass provides. There are actually two interesting bits of evidence for liquid water under the icy shell of Europa: 1) cracks in the ice crust appear to heal with time, and 2) the magnetic field around Europa is significantly smaller than would be expected since Jupiter has a substantial magnetic field. This happens near highly conductive bodies, such as a salty ocean perhaps.

The “heat plus water” equation seems to be more than enough for some of Earth’s extremophilic organisms, which bodes quite well for possible Europan biology. Given all of this it’s quite unfortunate that NASA somehow finds it more useful to waste oodles on a boondoggle to send humans to Mars rather than sending a much cheaper unmanned mission to Europa on a well-motivated search for extraterrestrial life. This despite the fact that we already have two wonderfully adept geologists on Mars right now living off of sunlight alone: the Mars Exploration Rovers Spirit and Opportunity. Here’s an example of two competing ideas regarding the Europan interior.

Alternative theories on the Europan interior.

Of course none of this says anything about the possibilities of complex or intelligent life. For that you probably need to satisfy much more stringent criteria such as the veritable Goldilock’s condition: a habitable planet must not be so far from its parent star that it gets too little light but also not so close that everything boils away. Getting the distance from the star just right is probably the most significant impediment to the development of intelligent life. Read more about the unfolding saga that is astrobiology here and here.

This might all be pure speculation since any would-be astrobiologist is forced to confront Fermi’s paradox regarding extraterrestrial life: if intelligent life is common why hasn’t it called us up yet? Or would it be too convenient for us to assume that another civilization would choose to communicate with us using radio-waves? Perhaps they’re so advanced that we can’t possibly hope to receive their communications given our limited technological capabilities? While although possible that’s not a falsifiable hypothesis and thus outside the bounds of science, but that won’t stop us from fun pontifications.