Currently, screening guidelines recommend CT testing for people with a 30-pack year history of cigarette smoking, or for former smokers who quit within the past 15 years. Those studies suggest that of those people diagnosed with lung cancer as a result of the CT, recommended treatment can result in a 20% reduction in lung cancer mortality compared with screening using chest radiography.
Patz and colleagues used data from the National Lung Screening Trial that compared low-dose CT with chest X-rays, which are considered to be as effective as no screening, performed on 53,452 people between the ages of 55 and 74 at high risk for lung cancer mainly because of their history of cigarette smoking.
What the researchers found was that the CT diagnosed 18.5% more people with lung cancer than did the chest X-ray.
Patz says that the research findings in no way suggest that patients at high risk should not undergo lung cancer screening. "But what we do say is that, for full disclosure, you need to let people know that there is this downside of screening." That's because for many of the people who are treated who didn't have clinically significant disease, "some will have inherent complications from their treatment," resulting in morbidity and mortality from the treatments and surgery, rather than the disease itself.