Monthly Archives: November 2011

Unhealthful News 185 – Cancer: screening is generally a bad idea; what about vaccines? (Part 1)

Yesterday, and several earlier times in this series, I wrote about how cancer screening tests have been shown to be inefficient (i.e., too expensive for the benefit they provide, as compared to competing uses of resources) or even more harmful than beneficial (a bad idea, even if they are free).  This is not quite always true, and refers only to mass screening of people with no symptoms and who are otherwise not believed to be at higher than average risk.  Cervical cancer screening is cheap and easy, and detects incipient cases of the disease rather than just finding growing cancers a bit earlier.  Most other cancer screening looks pretty bad on close inspection.  Maybe three or four mammograms between ages 50 and 65 are worthwhile.  
Finding a vaccine for cancer and administering it to everyone is possibly a different story.  About two weeks ago, the US government finally got around to recommending the HPV vaccine for boys.  It has been recommended for girls for a while because it was recognized that just about all cases of cervical cancer are caused by sexually-transmitted papilloma virus strains that the vaccine can prevent.  But beyond cervical cancer, it has long been recognized that HPV apparently causes many other cases of epithelial cancers (i.e., the body parts that are in contact with the outside world), specifically the bits that experience sexual contact, the oral cavity, esophagus, and anus.  So some commentators have asked “what took so long?”
That is indeed a good question.  There are a few answers that occur to me, one is fairly compelling, one is very compelling but no one seems aware of it, one is interesting and understandable but misguided, and two are deplorable.
The fairly compelling answer is that the vaccine is extremely expensive and prevention is probably of fairly little value.  Recall that screening is usually too expensive to justify; this is primarily because it is expensive to screen millions of healthy people who do not have the disease to find the few who have it.  It is also expensive to vaccinate millions of people who will never get cancer from HPV to save only the few who will.  However, when the prevention happens, in contrast with screening, there are no costs of false positives, no further treatment cost, and no damage from the disease at all.
Can screening ever look so good?  Not for cancer, given the high cost of treatment, but for other diseases it can.  The example that comes to mind is syphilis screening, which is mandatory in the US for pregnant women, in the sense that if they do not get the recommended screen during pregnancy then it is a mandatory part of medically supervised delivery.  Of all the screening tests I have ever done cost-benefit calculations for, this is the only one that came out clearly positive (note: I have never run the numbers for cervical cancer screening).  The reason that it is done is that syphilis transmitted to a newborn, if undetected, can be devastating.  But the benefits go beyond that, since non-symptomatic syphilis is unlikely to be detected, and so when it is detected the mother and her partner(s) are treated, eliminating those cases and all those they would cause in the future.  This almost certainly lowers the equilibrium prevalence of the disease in the population by a lot, perhaps by half or more.  But what makes this such a bargain is the treatment is relatively harmless and dirt cheap (a simple antibiotic shot), the cost of a false positive is equally low, and the cure is near certain and complete.  Unlike most cancer screening, this is a very good deal.
But a problem with the current HPV vaccine is that even though it does not entail further treatment like screening does, it is still very expensive.  It costs payers hundreds of dollars, in contrast with the few tens of dollars it costs to get a flu shot.  Merck charges $300 for the drug itself, and there is clinical time for three injections, plus whatever markup the medics add.  (Incidentally, the official claim is that the cost for vaccinating just the boys as they come of age would cost $140 million/year.  But since there are 2 million boys in every US one-year age cohort, this seems low by about a factor of five.  The estimate must be based on the assumption that few will follow the recommendations.  Or someone is lying. I will leave the investigation of that discrepancy to the news reporters.  Hahaha – just kidding.  They will never pursue it, and probably not even think enough to realize there is a problem.  Unfortunately, I will probably not investigate it either — if anyone does, please clue me in with a comment.)
What almost none of the unhealthful news reports bother to mention, however, is that this huge total expenditure is mostly not real resource costs.  That is, it does not consume actual stuff or labor, but rather just moves money from one entity to another.  Because drugs always are priced at greater than their manufacturing cost, because the price has to amortize development costs, and especially because the US does not negotiate drug prices like every other country and thus allows monopoly profit on top of that, that $300 price undoubtedly includes a huge profit for Merck.  While we might not want to give money to Merck, at least it is not an actual cost.  The same is true for the physicians’ fees for administering the injections.
A more important and compelling argument against the vaccine than purchase price is that this vaccine prevents cancers that, except in very rare cases, will occur at least 35 years in the future, and often decades more than that.  Those of you who know a bit about these analyses might point out that any proper cost-benefit analysis discounts future costs and benefits, so this delay is already accounted for.  But that process of discounting assumes that events will occur, and merely adjusts for the fact that we weight the present more heavily than the future in our decision making.  But is that a reasonable view?  Should we assume that oral cancer or cervical cancer (this observation applies to the girls too) will still be expensive or deadly disease that far in the future?  I certainly hope not.  Four decades might not get us to the point that a single injection will reliably eliminate the disease, as with syphilis now, but it seems safe to assume that there will be much better treatment than currently exists.  
Remarkably, I have never seen anyone else make this observation, other than me and some of my students (who were thinking this through as an assigned exercise with the advantage, compared to most people writing about such topics, of having been taught what to think about).  The strongest argument against this vaccine is that we should really hope it will not matter much for those who are currently young enough to benefit from it.  Consider how much the value of an expensive syphilis vaccine for children would have been overestimated in, say, 1930 (it became easy and pretty cheap to treat once penicillin was developed and proven in the early 1940s).
That is the good argument against the vaccine.  But I have never seen anyone make it, so it cannot explain what took so long.  In Part 2, I will look at the not-so-good reasons that probably do explain it.

Unhealthful News 184 – The right answer about prostate screening, but as for the reasons…

Sign in London Underground car

During my hiatus, Chris Snowdon asked for my opinion about a commentary by the Australian public health community’s own keystone kop, Simon Chapman, which argued that screening for prostate cancer is a bad idea.  Even though it was Chapman, the basic advice turns out to be good — after all, a stopped clock is still right twice a day.  (For more on why I am being so negative about someone who got the right answer, the above links go to Snowdon’s and my analyses of some of Chapman’s other “contributions”.)
To see why it was good advice, we need only look to something that came out a few weeks ago, in which a US panel led by Virginia Moyer, a former colleague of mine whose clock keeps perfect time, recommended that the common practice of PSA screening tests cease.  Here is Moyer briefly arguing for it in her own words.  An even briefer version:  Because most cases of prostate cancer are unlikely to grow fast enough to cause a problem before someone dies of something else, and perhaps the cases that will be deadly are unlikely to be prevented by screening, and because the treatment that results from screening kills some patients, it turns out there is no detectable mortality benefit from screening.  Meanwhile, the treatment often causes nasty side effects (impotence, incontinence).
Following this recommendation, there was the usual outcry against any recommended curtailment in wasteful medical spending.  It was the same as the reaction to scale back mammography that I wrote about before.  As always, the most remarkable comments are the breathless testimony from cancer survivors who are absolutely sure that the screening saved their lives, when obviously they have no way of knowing that, and indeed the statistics show that it is almost certainly not true. 
But what is a bit different about this case is how clear it is that the treatment, not the screening, is the real problem.  In contrast with a mammogram, a PSA test is not harmful and will never cause the disease it is meant to prevent.  Of course, the problem is that once someone screens positive, he is very likely to demand treatment even though it turns out to not be a good idea.  Still, the last chance to avoid the cost comes not from the decision to test, but from the decision that is made afterward.  Of course, if we agree that treatment after screening positive is a bad idea — and obviously the same is true for treatment after screening negative — then there is no value in screening other than to just know.
Those observations, in turn, led to a spate of occasionally interesting articles about whether it is better or worse to know.  A lot of the discussion came back to how difficult it is to just live with the knowledge rather than acting on it, even if acting is not beneficial.  The decision to treat is what actually causes the harm, but since that apparently bad decision is inevitable following a positive screen, the only way to avoid the mistake is to avoid the triggering knowledge.  It makes sense, but it is still interesting that people cannot resist acting.  
The above-pictured “In an emergency” sign from the London Underground is really amusing, with its major point of advice being “Do not take any risks”.  What it is really trying to say (I assume) is to favor inaction over action until advised to do otherwise, which is quite often terrible advice and obviously entails some risks.  But someone apparently calculated that it is good advice, on average, for subway emergencies, and it turns out to be the right advice for treating the average detected case of prostate cancer.
To finish the story I began with, Snowdon’s incredulity about Chapman’s advice did not focus on the overall merits of the advice itself, but rather on how Chapman tried to support the claim:  He made a wandering argument in which he suggested that screening and treatment does have mortality benefits, but since prostate cancer kills mostly old men who have already had a good life and might die of something else shortly anyway, they should favor quality of life (avoiding the damage from the treatment) over longevity.  Snowdon pointed out the strangeness of this argument that men should not have the option of going for the supposed longevity gains, coming as it was from someone who is best known demanding the opposite choice.  Or, more pointedly, known for his willingness to pervert science, abuse the social contract, and do pretty much anything he can think of that might keep people from choosing to smoke or even choose to be in smoky environments.  He will ferociously fight to deprive people of the choice to take that risk, however much their lives might benefit from the choice, but then demands that men accept another mortality risk because he judges that their lives will benefit.  
The funny thing is that, according to Moyer et al., it is reasonable to deprive men of this choice because there seems to be no upside.  But Chapman claimed there is an upside to treatment, but that the choice to pursue it should still be denied.  A slow clock, rather than being right twice per day, might only manage once per month.

Unhealthful News 183 – Greetings from the middle (of history (of science))

Hello, everyone.  I promised you 180-some more UNs, and while I will obviously not fulfill my hope of doing that within 2011, I will continue toward the goal.  I will get started by including some general observations I have been wanting to write about, interspersed with the unpacking of recent news that is the central theme of the series.
This is hardly the first time this has occurred to me, but I have been struck over the last few months by how most people, notably including those with the experience to know better, seem to think that they are living at the end of the history of science.  People who understand how Newtonian physics, which seemed doubtless correct for centuries, had errors that were fixed by Einstein’s relativity are remarkably unwilling to allow for any possibility that the current theory has some flaws, such as the possibility that a particle could move faster than the speed of light.  Of course, I am more interested in science and technology that is more immediately practical.
One place I observed the phenomenon of people not realizing they are living in the middle of history is with regard to “renewable energy”.  I have been in some interesting battles about industrial wind turbines, which regular readers will know cause serious health problems for nearby residents and are so incredibly inefficient that they arguably offer no benefits at all.  I will come back to some details of what I have written and been dealing with there, but will start with my observation about what seems to be motivating some IWT proponents.
I have noticed that the well-meaning people (i.e., I am not talking about the industry and their hirelings) who argue in favor of building IWTs persistently fail to understand the technological reality that we are not at the end of history.  Their view seems to be the following:  The natural dynamics of the planet — wind, waves, sunlight, temperature gradients — contain plenty of energy that should be harvestable for electricity.  Moreover, we will probably (they would say inevitably) come to need those sources of electricity.  Typically they also point out that burning coal has huge environmental costs.  But the erroneous syllogism is the next bit, where they argue, “…and therefore, since the only technology that harnesses those dynamics that can be built on a large scale right now is IWTs, must be a good idea to build them.”
I assume the gaping failure of logic here is obvious.  Decades or centuries before the Apollo Program, it was clear that it was possible to use develop technologies to send people to the Moon.  But that did not mean that getting aboard the best rocket that could be slapped together in 1950, wearing a diving suit, would have been a bright idea.  Yet when I or others point out that (a) IWTs are so incredibly inefficient that their net contribution to energy generation is quite possibly negative (i.e., installing new IWTs actually increases fossil fuel consumption), and even if the contribution is actually positive, the cost of that tiny benefit is enormous, (b) IWTs cannot affect baseline generation like coal or nuclear (which basically need to operate at full capacity all the time) because the wind is intermittent, and so only affect how much gas is burned (gas plants can be turned on and off — it is not terribly efficient, but much better than it would be with coal), and (c) IWTs do terrible damage to local residents’ health and the environment, I frequently get the response “but we cannot burn fossil fuel forever! and coal is evil!!!”  
Translating that charitably (i.e., resisting the very strong urge to scream “what part of ‘approximately zero net energy contribution’ and ‘does not replace coal burning’ is too complicated for you to understand?”), I can only conclude they they are falling victim to the end of history fallacy.  Since at some point in time we might be forced to get our electricity from “renewable” sources, and improving technology will make such generation efficient long before then, then doing so must already be a good idea.  After all, how could something possibly be a good idea in the future, but not a good idea now?  Aren’t we the pinnacle of human civilization?  The evidence-based truth, that renewable technology (except for damning rivers for hydroelectric) is currently not ready, and thus immediate installation is a terrible idea, simply cannot penetrate that prejudice.  
A second version of the “end of the history of science” fallacy can be found in blind faith in the perfection of current health science methods and knowledge.  This problem explains much of the unhealthful research and news reporting I have covered in this series.  If only there were a bit of epistemic modesty and use of the phrase “the best we can do now” or “given the limits of current knowledge”, there would not be nearly so many errors in health reporting.
Allopaths (mainstream Western medics) are particularly guilty of lacking modesty, epistemic and otherwise, and the tendency to mistake medics for scientific thinkers is particularly damaging to health science.  For a profession that so recently engaged in such practices as therapeutic blood letting (which physicians of the time were absolutely positive it was a good treatment) and was quite likely to kill those it was supposedly helping because physicians refused to wash their hands (and were absolutely positive that doing so would be madness), medics and their enablers show a remarkable arrogance in insisting that everything they currently believe is absolutely, positively, beyond-and-doubt correct.  What is worst, >99% of the time, the belief is not based on any scientific knowledge, but rather was just something someone was told.  And so they believe it with certainty.  If this this sounds a bit like another major social institution that has a history of being absolutely sure of highly destructive baseless claims on the basis of faith alone, you are not wrong.
I am not just talking about how many clinicians are absolutely positive that smokeless tobacco is highly risky and other areas where they are the victim of directed propaganda (though there is no excuse for that either).  I am talking about things like medics whose education includes the equivalent of one semester of epidemiology, one semester of immunology, and zero semesters of nutrition making absolute pronouncements about the evidence about food allergies, and often being very wrong.  I’ll probably come back to that theme.
At a less dramatic level, the “end of history” mentality contributes to the reporting of every trivial, highly-technical research finding as if it were of huge practical importance by itself.  This is not the only reason for that, of course, and I have written extensively about some of the others.  But if consumers of the report (editors, reporters, consumers, policy makers) understood that they are sitting in the middle of history, they would not be so vulnerable to venal self-aggrandizement by researchers.
The metaphor that occurred to me is that this is like polishing roadway gravel.  Gravel is very useful in a workaday way, making it possible to move forward over otherwise muddy terrain.  But picking up a piece of gravel, polishing it to a high sheen, and putting it in a glass case does not make it a gemstone.  In a way, the unpolished bit of the road forward was arguably contributing more to the world than a gemstone.  But even if you do not take such an extreme workmanlike view of value, it should be clear that trying to polish and display a large portion of the gravel is a disservice to the value of both gemstones and gravel.
So, we should not polish the gravel, but should wait until we reach the end of the road where there will be a gemstone.  (Hint for interpreting that: like a rainbow, the road has no end, so that statement, like the one about the pot of gold, is true because it is vacuously satisfied.)