Wednesday, November 24, 2010

Scientists say "Don't worry" start worrying !

The latest Scientists Say bulletin is that the x-ray machines in your nearest airport are not-to-worry.  Yes, x-rays cause cancer, but no, our company that makes these machines, and the Government that has signed off on them, free of course of any vested interest, says these are 'safe'.  What that means is safe for their jobs, because at this stage someone who tells some truth will lose his or her job.  Today the NYTimes has a story on risks of dental x-ray machines.

The problem is that even when the machines work, and the tech operating them actually knows what s/he's doing, they expose people to one of the world's best-known carcinogens.  When a scan (including a CT scan, not just something called 'x-rays', by the way) is done for therapeutic or truly diagnostic reasons, then the risk-benefit trade-off seems clear.  But dentists and docs often just want to 'take a look', or add to your bill, or play with toys that make them feel important and intelligent.  Or they themselves have little understanding of the risks of radiation carcinogenesis.

Of course, government bureaucrats will always deny that they've allowed us to be exposed to risks.  Remember dismissals of HIV (only our social scum get it, if you Africans (who cares about them?)).  Or mad cow disease in the UK.  Or from Canadian beef?  Or the possibility that New Orleans would flood. Or many others like these examples.  Or climate change...ever heard of that?

The point is that scientists and governments cannot automatically be trusted. They (we) have all sorts of clear and covert, known and perhaps unaware, vested interests.  Some do indeed state warnings, and not all of them (us) are perfect in that. But the typical story, it seems, is that over-worry is discouraged because the interests often lie more heavily in the drill-baby-drill contingent than the cautious one. There's usually little profit in being cautious.

There are no easy answers that we know of in regard to airport security. We don't travel by air much because it has become a frequently miserable experience.  And it's clear that if we staunch one vulnerable point, terrorists will search for another. Unfortunately, however, the 'facts' seem to be elusive in just the cases in which these issues are most important.  The problem is, of course, when risks are so small, as in the case of airport x-rays, as to be basically immeasurable, but we have biological reason of decades' standing to know that they are not zero.  And they are greatest to the youngest, to premenopausal women, and so on.

What we're witnessing, unfortunately, is a huge victory for the bin Ladens of this world.  One looney-toon puts some explosive in a shoe, and tens of millions of people have to take their shoes off in airports.  One sad case loads up his undies with something, and we're all going to get a scan or a pat where the sun don't shine.

Meanwhile, we all learned recently that cargo is many times more vulnerable than passengers to being loaded.   Again, while we have no answers, it is clear that the current x-ray approach is too good for business to be denied.

1 comment:

Ken Weiss said...

A major purpose of a blog is to offer opinions that may not get airing otherwise. We feel it is responsible to post measured reaction, even if it's negative. But we don't post abusive or irresponsible comments.

In the spirit of disclosure, however, we received an abusively angry comment from a dentist who defended the use of dental x-rays and accused us of saying that such uses were the latest 'scam'. The commenter refused to identify himself and ranted in ways that did not reflect what we actually said in our post.

Among other things we did not suggest that such kinds of exposure were categorically of no use but we did suggest that there is a general tendency to over-use and over-defend testing in the health professions when the risk doesn't match the benefit. That fact is widely acknowledged, as is the potential that health professionals may have other vested interests in over-testing (including financial involvement with the testing lab, or protection against malpractice lawsuits). We have personally observed careless use by poorly trained people (and we're not in a poor-care area), as well as just take a look.

Our invective-laden practitioner who claims to have 12,000 dental patients even defended dental x-rays to identify cadavers, as if we had said that was poor practice!

But of course as we DID say, when there's a good diagnostic or therapeutic reason radiation is very useful if not life-saving. That is where invasive techniques have their best legitimate role.

As we noted, the problems with many of these exposures are first, that the risk is so small that direct causal attribution in individual cases (e.g., of salivary and other tumors from dental x-ray exposure) is statistically impossible, though we know there's a risk (there is scientific literature on this, besides the recent NY Times story). Secondly, exposures such as to ionizing radiation probably are cumulative, so that too much casual exposure earlier in life can raise the risk of iatrogenic disease when later treatments are applied.

The use of mammography is a clear and controversial example: how many cases of breast cancer does routine testing cause vs how many does it detect (or does it lead to over-treatment of detected lesions?).

Likewise, PSA testing to detect early prostate cancer in men is now controversial if not actually considered not the best practice: too many benign lesions are found, and lead to intervention that may not have been necessary but carries risk.

These are live issues that we did not invent. If there was no risk, why do technicians leave the room before pushing the 'zap' button, and why do they cover you with a lead apron? And why are pilots and stewardesses exempt from the new airport scanners?

The answer, an appropriate one, is that many exposures could lead to measurable risk. But that doesn't mean that everyone should be given lesser exposures unless there is a clear reason.

Careful use of medical procedures, including non-test-happy use, is fine and we didn't say otherwise.