In the wake of Peter Jennings' death from lung cancer caused by smoking, a debate over the usefulness of CT scans as a screening tool for lung cancer in current and ex-smokers has emerged.
The argument in favor of using chest CT scans for lung cancer screening in current and ex-smokers is that this procedure can detect tumors far earlier than they are normally detected (based on the appearance of symptoms or the appearance of tumors on conventional chest X-rays). With earlier detection, definitive treatment for lung cancer is more likely to be possible, resulting in a reduced death rate from the disease.
The argument in opposition to using chest CT scans for lung cancer screening is that there is not yet any documented evidence that the procedure will save lives yet there is substantial evidence that the procedure will result in a large number of false positive tests, creating widespread anxiety among patients and requiring the use of additional screening or in some cases, invasive and risky diagnostic procedures. In addition, there is no evidence that the benefits of the use of this procedure as a screening tool would outweigh the costs (estimated at $39 billion on a national basis).
The Rest of the Story
Although it would be tremendously beneficial for there to be an effective screening test that could detect lung cancer at an early and treatable stage, there is unfortunately no such screening test presently available.
First, there is as yet no published evidence that spiral CT scanning is effective in reducing mortality from lung cancer via the early detection of tumors at a treatable stage. Until such documentation is available, it would be premature to recommend this procedure as a screening test on a population level.
Second, the false positive rate is currently far too high to make spiral CT scanning effective and appropriate as a population screening tool. Use of such a screening procedure on a population basis would result in millions of patients with false positive results, creating widespread anxiety, requiring intensive follow-up screening, and in some cases, necessitating the use of invasive and risky diagnostic procedures.
Third, because of the first two problems, it is not at all clear that the cost of population screening for lung cancer among smokers and ex-smokers would be outweighed by the potential benefits.
In summary, there is simply no justification at the present time to support the recommendation for chest CT scanning on a population level for screening for lung cancer among current smokers or ex-smokers.