06 November 2011

Unhealthful News 186 - Cancer: screening is generally a bad idea; what about vaccines? (Part 2)

In my previous post, I noted that there were several arguments made against recommending (or, for that matter, mandating) HPV vaccines for pre-sexual children, to protect against that sexually-transmitted cancer-causing virus.  The one of these arguments that is actually fairly compelling, that the cancers the vaccine could prevent could very plausibly become easy to treat during the >30 years before they will occur.  But since almost no one seems to understand this, it is interesting to try to understand what took so long to make the recommendation that boys get the vaccine.  I noted that there was one misguided and two deplorable apparent reasons for that.

The first of those is that, in contrast with cancer screening, vaccines provide no stories of miraculous life-saving success.  Well, actually that is true for screening too.  There are lots of stories, but they are usually wrong.  That is, most people who are uncritically quoted in the unhealthful news reports, in any story about a particular screening regimen looking like bad idea, sobbing "I am living proof that this screening saves lives!" are probably wrong.  Most such screening tests detect many cancers that never would have led to morbidity, and others that would have been detected and successfully treated without that mass screening.  In other words many, often most, of the "saved lives" were not.  But they make a good story for the statistically illiterate decision makers, and are enough to let them be talked into funding/recommending/mandating the screens by those who stand to profit from that policy.

There is no such misguided constituency for vaccines.  No one realizes that their life was saved from a disease they never got.  Indeed, this is undoubtedly why vaccines for infectious agents that have other nasty effects are often forgone or even hated.  News stories never report on the person who insists "I would have died without that vaccine", even though the speaker would be no less certain than someone making that claim about the screening test.  Perhaps some of us should form a patient advocacy group as survivors of polio who never got it thanks to vaccination.

I will leave that for another day and move on to the even worse reasons the HPV vaccine has been only reluctantly embraced.  HPV can be transmitted sexually even if condoms are always used.  This means that, absent the vaccine, HPV risk is a reason to avoid even "safe sex".  While it is obviously not a reason that affects behavior to any measurable degree, as evidenced by extensive journal peer reviewed...  just kidding, I meant: as is obvious to anyone who is not totally clueless.  But that incentive, or more accurately, that opportunity for anti-sex propaganda, is something that those who want to scare people into not having sex do not want to lose.  Some have said as much, while others clearly share that sentiment but pretend to have other motives.  They are quite willing to hurt people to save their souls or whatever.

If this sounds familiar to many of my readers, it should.  It is basically equivalent to the anti-harm-reduction tactics used by anti-tobacco extremists.  In both cases, prohibitionists actively oppose making the activity in question less risky because they want to maximize the incentives for abstinence.  But that is not the only deplorable connection.  It seems fairly likely that one reason the recommendation boys get the vaccine (rather than just girls, to protect against cervical cancer) was so long in coming was because of the refusal to recognize that for at least a decade the evidence suggested an increasing number of oral cavity cancers are caused by HPV.  Indeed, many of the articles about the new recommendation have emphasized protection against anal cancer and anal warts, probably trying to create controversy by making it "a gay thing" and mention only throat (esophageal) cancer in addition to that, mysteriously not mentioning the dreaded oral cancer.

Why the failure?  It is difficult to say for sure, but it is also difficult to not attribute it to the anti-tobacco extremists claiming oral cancer as "their" disease.  They use it for misleading people into believing that smokeless tobacco poses substantial disease risk and is responsible for a growing epidemic of oral cancer.  There has never been the slightest doubt that smoking causes far more oral cancer than smokeless tobacco, but the notion that "switching to smokeless just trades lung cancer for oral cancer" has been a major contributor to delaying tobacco harm reduction for years.  The extremists -- pretending to be concerned with public health, just like the "Christians" who would intentionally avoid curing the lepers if leprosy was sexually transmitted -- got this myth so well established that it is quite difficult to communicate the causes of oral cancer.

There is a certain elegant symmetry in it.  The lefty pseudo-"public health" sermonizers who despise the right-wing anti-harm-reduction sermonizers who oppose safer sex or needle exchanges have ended up working in tandem with them on this issue.  Maybe it will be a wake up call to them and they will... just kidding again.

Finally, the symmetry extends to that one good argument I noted.  Just as an 12-year-old who gets the HPV vaccine will be protected from a disease that will not occur for decades, and might be quite easy to deal with by then, a young person who picks up a dangerous behavior now might be saved by advancing medical science.  The analogy is far from perfect:  HPV-caused cancer is a specific cancer that, if fully cured or prevented at the last minute, might do no damage.  By contrast, smoking damages lung and other tissue over time, and contributes to many diseases in complex ways, and that damage seems a lot less likely to be able to avoid or reverse.  On the other hand, if smokeless tobacco causes an oral cancer in someone who starts using it now, the evidence suggests that this will happen many decades from now, making it again like the HPV case.

So, screening is loved based on non-evidence; vaccine-based harm reduction for sexually transmitted disease is embraced by the health authorities but suspect among some political factions; uptake of that vaccine is limited, though no one seems to be motivated by the one good reason for not bothering with the vaccine; the oral cancer vaccine is not being recognized as such; and none of this will affect the behavior of the various extremists and activists.  The funny part, and the only reason this is not completely mortifying, is that a remarkable amount of the stupidity/naivety/dishonesty is canceling out other bits of the stupidity/naivety/dishonesty.

1 comment:

  1. I was arguing in the pub over the weekend about the blatant sexism of the UK government for offering all women (not men) caesarean sections.


    My point was that why should I as a man be refused this offer. Just because I am male and therefore unlikely to want such a procedure is no reason not to offer it to me and considering
    that it is highly unlikely that men will take up the offer and because it will cost the NHS nothing to make the offer, there is no sensible reason not to make the
    offer, it's just plain sexism. This was all quite tongue in cheek of course but if I had had my wits about me, I could have made the point that in 30 years from now technology
    may change and maybe men will be able to be in a position to need caesarean sections! Next time I shall make my case better still!


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