chest xray

Best strategy for discovering lung tumors are the more costly CT scans.

Chest X-rays done annually didn’t significantly reduce the death rate from lung cancer in a study involving more than 150,000 patients that reflects the challenges of using early detection to save lives in the battle against malignancies.


The findings suggest the best strategy for discovering lung tumors in an early, more treatable stage is screening with more-costly CT scans, which were shown in a separate recent study to lower the death rate by 20% despite a high percentage of false-positive results.

“There was no discernible benefit from chest X-rays,” said Christine Berg, chief of early-detection research at the National Cancer Institute and senior author of the study. “This provides the definitive answer to the question.”

The results, from what is called the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, were presented Wednesday at the annual meeting of the American College of Chest Physicians and published online by the Journal of the American Medical Association.

Previous findings from the study showed, among other things, that a screening test called CA125 failed to reduce the death toll from ovarian cancer. In another blow to early-detection efforts, the U.S. Preventive Services Task Force earlier this month urged against routine use of the popular PSA test for prostate cancer, saying potential harms outweigh its benefits.

Lung cancer is the leading cause of cancer death in the U.S. and globally, and is mainly caused by smoking. The American Cancer Society estimates 221,130 new cases of lung cancer will be diagnosed in the U.S. this year while 156,940 people with die from the disease, accounting for 27% of all cancer deaths. Regular chest X-rays have long been considered a strategy for screening patients considered at risk. Earlier studies didn’t show a benefit for the approach, but flaws in the studies’ design had left researchers uncertain about a potential role for X-ray monitoring.

In the new study, funded by the NCI, patients between 55 and 74 years old were randomly assigned to either a regimen of annual X-ray screenings for as long as four years or “usual care,” which didn’t involve any scheduled X-ray tests. About 45% of the participants reported never smoking, 10% were smokers and the rest were previous smokers when they enrolled in the study. Half of participants were women.

During a follow-up of as long as 13 years, 1,696 cases of lung cancer were detected among those in the screening group and 1,620 among those not routinely screened. There were 1,213 deaths from lung cancer in those in the X-ray group and 1,230 in those who didn’t get the tests, reflecting a death rate that was nearly identical statistically.

Of the 1,696 cancers diagnosed among those in the X-ray group, 307 were detected by the test itself. Another 198 were found during the four-year screening period, but when patients developed symptoms in between screens. The rest, or about 70% of the cancers, were found during the years after the screening period ended. The findings indicate patients who opt for regular screening are much more likely to benefit from a CT test than a chest X-ray. Dr. Berg said chest X-rays in the study cost between $50 and $85, while CT scans were about $370. But some centers charge more than $800 for the CT test, she said, which isn’t typically covered by insurers when used for screening purposes.

Dr. Berg said the results mean the challenge for researchers is to improve CT scans to reduce the rate of false positives, which can lead to additional tests that are expensive and, in a small number of cases, complications from those tests. In the recently published National Lung Screening Trial, she said, 95% of the abnormalities detected by CT turned out not to be cancer.

In contrast to the current study, the study showing a benefit of CT scans enrolled only people with a history of heavy smoking. In addition, in that study, the scans were compared against chest X-rays, while in the current study, the comparison group didn’t have any recommended screening tests.

Robert Smith, senior director for cancer control at the American Cancer Society, said the new study left open the possibility that regular annual X-ray screenings beyond four years might have turned up a benefit, but generally, he said, “chest X-ray is not the test to use to rule out the presence of lung cancer.”

He said the findings call for development and testing of other approaches beyond CT scans to find more effective methods of detecting lung cancer early.

Via Wall Street Journal