The National Cancer Institute announced a few weeks ago that spiral CT scan for smokers with at least 30 pack years (Number of packs per day times number of years smoked) lowered risk of death from lung cancer by 20%.
This is genuinely good news. There is a long history of trials of screening smokers and former smokers for lung cancer showing that the risk of death was higher in the screened group than the nonscreened group, presumably because of the harm caused by biopsies and surgeries in a group with limited lung capacity due to the ravages of smoking. The current study is huge (53,000 patients), and it is well-designed. It was not funded by any party with a vested interest in a positive result. I’m surprised at the results – but good science doesn’t always confirm our prior beliefs.
Here’s bad news, though. One imaging center in
put out a press release the same day saying “"It is clear that in patients at risk, particularly those who have smoked for over 10 years, this is an indispensable part of your annual examination.” California
This misstates the results of the trial significantly, and would lead to a large number or spiral CT scans, with much expense and radiation exposure. Screening can be effective with a high prevalence of disease. When the same screening is applied to a lower risk group, the risk of false positives climbs dramatically. At some point, the cancer from excess radiation outweighs the benefit of potential earlier cancer detection –although we don’t know what that point is. The New York Times had a well-balanced article on this.
The medical director of that center said “We know from our own anecdotes that we have saved a lot of lives.” That’s a highly unscientific statement. Anecdotes don’t tell us we’ve saved lives – well designed trials do. We need more comparative effectiveness research. Once we’ve done the research, we should provide coverage for effective diagnostics or therapy. We should NOT pay for services that have not yet proven to be effective except as part of a trial to determine whether these services bring benefits to patients.