SMOKERS, SHOULD YOU GET YOUR CAT SCAN?

SMOKERS, GET YOUR CAT SCAN

The push is on for smokers and non-smokers to get a CAT scan.  The message is that it will catch tumors when they are small, and they can be removed before they spread.

Lung cancer kills over 160,000 of us a year.  If more tumors can be caught early, many lives could be saved.  Every one of you 45 million Americans is a prime candidate for this lung imaging.

Most  people agree on how good a CAT scan has become since 1995 when CAT scans were created.  The detectors now spin and slice through the body in 5 seconds.  An image can be taken in a single breath.  A computer can tune some densities in and out and make a 3D view of tissue and bone.  A scan might have 256 slices and a 0.3 mm square can be well visualized.

What happens after your initial scan?  If you have a nodule 5mm or a cyst 8mm you would probably get a biopsy and then possibly surgery.  At least you will be asked to come back in 3 months for another scan.

The logic is hard to argue with.  If you can find a small cancer at an early stage, why not go for the CT screening.  If you don’t treat it, you will die.

PROBLEMS

All this is based on a screening study on 32,000 people 40 or older, called I-ELCAP.  The study is riddled with flaws.  There never was an outside audit of their data. 

The procedures are very lucrative.  The initial CAT scan may be about $300, but that’s just the down payment with much more to come.  This results in all kinds of medical business.  There will be follow-up scans, biopsies, and other tests.  Since the people in the study were not picked at random, but  were smokers, it is markedly twisted.  The intense screening can flag many non tumors  or slow growing tumors as dangerous,when in reality they are nothing.  Over diagnosis can boost the number of people diagnosed with cancer and appear to recover from it when they don’t even have cancer. 

Another study, by Bach published in JAMA last year, this one  a random study, found no evidence that screening reduced the risk of death from lung cancer in 5 years. 

Biopsies were done 3 times more often than needed and lung surgery 10 times more than needed.

The basic principle of CT screening is wrong, says Bach.  Most of the lung cancer that kill come like a meteor, out of nowhere and is everywhere.  Screening is not going to catch them.

Random studies?  Is it ethical to recruit normal non-smokers with a promise of a high quality diagnosis and then give chest x-rays?

There is a fierce battle between a patient advocacy groups, Lung Cancer Alliance funded by GE the makers of Cat Scanners, and the National Lung Screening Trial by the federal government and the National Cancer Institute. 

The tobacco industry is fighting annual screening and feels it would set a precedent.  The tobacco industry gave $3.6 million to Weil Cornell Medical College in New York city to speak about the uncertainties of CT screening and the potential risks to people who might sign up for the study.

Those researchers doing the current CT study have a financial interest in the CT invention to be used with CT screening and have 27 patents for lung screening.   They receive royalties from General Electric who makes the CAT Scanners and have licensed the patents to GE.

 The National Cancer Institute has spent over $200 million on this Lung Screening Trial, which will be finished in 2010. 

Perhaps the air will clear by then.  In the mean time, could we spend some of this money on curbing smoking?  After all, this is the major cause of lung cancer.

Sources: Bach @ Memorial Sloan Kettering Cancer Center,  Science, May 2, 2008

What do you think?  Your comments are always appreciated.

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