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TOTAL BODY SCANS, VIRTUAL COLONOSCOPY FOR BOWEL CANCER, HELICAL CAT SCAN FOR LUNG CANCER - A LOT OF HYPE, BIG PROFITS, INADEQUATE EVIDENCE, AND POTENTIAL HARM

(April 2002)

According to those advocating these technologies, these are the advantages:

- the total body scans will detect abnormalities and diseases virtually anywhere in your body at such an early stage that progression of the disease or abnormalities can be prevented

- virtual colonoscopy, done by a computerized scan, will detect bowel abnormalities that could lead to cancer

- helical CAT scans of the lung will detect very small cancers that can be removed with resulting cure rates of 70 to 80 percent.

It all sounds great. It is supposed to sound great; after all, if a lot of people undergo the tests, one guaranteed result is that the doctors conducting those tests will make a lot of money.

What do we actually know?

- Total body scans: Definitive studies to document its benefits or dangers have not been completed. Almost certainly, there will be a lot of false positives that will require expensive work ups that could cause serious, even fatal, adverse effects. Will total body scans reduce the frequency of occurrence of or deaths from serious diseases such as heart disease, stroke, or cancer? At present, we do not know, nor do we know how often the test will miss important abnormalities or diseases, thus giving the individual false confidence that nothing is wrong.

- Virtual colonoscopy: This has real possibilities, but we do not know whether the test is as good as a real colonoscopy in which the bowel is studied by insertion of a flexible tube that will directly visualize any abnormalities. We do not know how many abnormalities will be missed and how many findings will be false positives. One investigative study found false positive rates between 8 and 19 percent; when, in general use, that rate could be even higher. What is sure is that virtually all the positive findings on virtual colonoscopy will have to be confirmed by a followup full colonoscopy. If the true positives (mainly polyps - benign growths that could become cancerous) are added to the false positives, those needing regular colonoscopy after virtual colonoscopy would likely be in the 20 to 40 percent range. That is a huge percentage.

- Helical CAT scan of the lungs for cancers. This, too, has real possibilities. It does detect very small cancers. The problem is that there are as yet no studies that show it saves lives; and the only true measure of a screening test for cancer of the lung is that it actually saves lives. In addition, there are recent studies that show that detecting lung cancers when they are very small does not appear to result in reduction in deaths. A major concern is the frequency of false positives that require further work up, including, for some, invasive, potentially dangerous procedures. The proponents down play the false positives; others suggest false positive rates of 20 to 50 percent. Helical CAT scan is now undergoing trials to determine whether it does or does not save lives; until those studies are completed, statements claiming helical CAT scan can result in very high cure rates (up to 80 percent) for lung cancer are undocumented hyperbole.

One thing is for sure, these tests are expensive. One imaging center in New York is advertising a combination of total body scan and virtual colonoscopy for $1,400 each time. If done every five years, together with the work ups for the false positives, total body scans plus virtual colonoscopy would cost, on an annualized basis more than the entire Healthful Life Program.

The bottom line is the following:

- It is hard to figure out any reason to recommend total body scans.

- A full colonoscopy every ten years is currently the Healthful Life recommendation starting at age 45 (others start at age 50); an alternative is flexible left-sided bowel examination (sigmoidoscopy) every five years. Virtual colonoscopy can only be regarded as experimental until more data are available. It does have the potential to be very useful; so it is interesting, but not yet adequately documented.

- Helical CAT scan cannot be recommended, at present, as an effective screening procedure for lung cancer. We must have proper evidence, not just the hopeful claims of the enthusiasts.

We do need good health promotion-disease prevention screening. That is what the Healthful Life Program represents.

CLICK HERE FOR OUR PROGRAM (THE HUMAN TUNE UP)

Bad screening, especially expensive undocumented screening, interferes with good screening. There just is not enough money to pay for both good screening and undocumented screening. Excessively expensive health promotion-disease prevention because of ill-documented screening will severely damage the American health care system and, in so doing, will undercut attempts to get the American public to follow sensible, documented health promotion-disease prevention.