Screening for lung cancer must wait for better evidence
BMJ 2007; 334 doi: https://doi.org/10.1136/bmj.334.7593.558-a (Published 15 March 2007) Cite this as: BMJ 2007;334:558
Screening for lung cancers with computed tomography (CT) remains an experimental and unproved intervention that may do more harm than good, says an editorial. There's no consistent evidence that screening saves lives, even when offered only to heavy smokers. But it does increase the chance of invasive tests, biopsies, or even a resection. Mortality after lung resections is about 5% in the United States⇑.
The editorial's authors were commenting on a cohort study of 3246 current or exsmokers who had at least three annual CT scans (pp 953-61). The scans detected three times as many cancers as would have been expected without screening (relative risk 3.2, 95% CI 2.7 to 3.8), and resulted in 10 times as many resections (10.0, 8.2 to 11.9). But screening did not reduce the risk of an advanced cancer and had no overall impact on mortality (1.0, 0.7 to 1.3).
This kind of study is always a compromise, however. The researchers had no control group, so they used a prediction model to guess what would have happened without screening. It's possible the model was biased, and the researchers warn that their findings are preliminary.
Randomised trials under way in Europe and the US should tell doctors and smokers exactly what they need to know about the risks and benefits of lung cancer screening with CT. In the meantime, even enthusiasts should reserve their judgment.