Friday, December 21, 2007

The American Dental Association’s Failure to Look at the Data Critically on Oral Cancer and Bush Biopsy


You would think that an organization that is made up of doctors would get things right. Let’s start with the misrepresentations in their current advertising campaign about early detection of oral cancer using a brush biopsy system, more commonly known as brush cytology. In my previous postings I have stated that one of the main features of their awareness campaign that is wrong, is that it bypasses the initial requirement of discovery. But now that some of the really knowledgeable people (from the world of science and research) have looked at this, more has come to light.

First, in the ads it shows a specificity and sensitivity in the 90 percentile, with the initials NCI next to it. The numbers did not come from the NCI, nor have they evaluated this system according to calls made to them. The numbers actually come from a study funded by Oral CDx in Germany by Christian Scheifele et.al. How the ADA or anyone else who put this ad together ties that article, which was published in an Elsevier journal, to the National Cancer Institute is very unclear, and perhaps even deceiving.

To restate the obvious, since its use began in the 1920’s brush cytology, or if you want to use the branded term “brush biopsy” now from CDx, has had specificities and selectivity numbers in the 50-60 percentile range. I guess you would have to ask yourself how something, that in numerous studies showing this, would suddenly leap into the 90 percentile level. Actually, it just a matter of poor study design. When CDx did their studies, as a prelude to their marketing campaign, they included in them both class I and class II lesions.

If you are not familiar with what this means, in the simplest of terms, a class I lesion is advanced to the state that your suspicion that it is cancer is high. It is an open ulceration, it is bleeding, it is cratered, etc. it has characteristics that send lights and bells going off in your head when you look at it. In short your paperboy could look at it in your mouth and guess that it was something dangerous and likely malignant. The CDx system is NOT designed to be used on class I lesions, they say so themselves, and were it used in that manner, the person doing so would be doing the patient a disservice as well. Anything that obvious needs to be biopsied using a gold standard technique, not a brush. Class II lesions are small and early developments, that it would be hard for anyone to visually determine that they were something benign, or dangerous. This is what the Oral CDx brush is designed to evaluate.

But if you look at the company sponsored studies carefully, you see that they include in the lesions evaluated, a significant number of class I lesions. It would be one thing if these were used as a “control” in the studies, but they are not. They are lumped in with the class II lesions. What happens to the numbers if you take the class I lesions (which without testing visually scream “I’m dangerous”) out? The specificity and sensitivity of the CDx system goes right back to where you would expect to find it… in the mid 50% range. Right where brush cytology has always been.

The ADA is counting on the fact that the public does not understand all this, and for that matter, I bet the bulk of the general dental professional population does not either. That the ADA has rushed into all this without looking carefully at the data, (after all, this is not their first dance with Oral CDx, they did a similar billboard campaign in 2001 with the company)without consulting recognized experts in the field, has put their logo on what is nothing more than a misleading advertisement from a product manufacturer; because they are either too lazy, or lacking the ability to design their own program, or unwilling to spend their own money on it, is really pathetic. The more I look at this the more it stinks. Yes, oral cancer and detection are getting out there in the media, but the message is wrong. I wonder when the dental community is going to pay attention to this and ask their professional association to discontinue this money-motivated ruse, or to at least quit rubber stamping the commercial company's marketing program, and put out ads that state this in a scientifically correct manner.  At least this current ad that I saw didn't say "We can prevent oral cancer." 

I have said it before and I say it again. You wish to bring the death rate down from oral cancer it is through early discovery…. This program is based on diagnosis, and talks little about the most important component, opportunistic screening of dentist’s entire patient populations where early discovery will take place. No opportunistic screening = No early discovery = Nothing to biopsy with the brush or anything else. The message is FIRST about getting screened guys; eyeballs, fingers, ancillary devices, by a non complacent group of professionals. THEN it is about diagnosis. 

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