Screening with Chest X-Rays Does Not Reduce Lung Cancer Mortality
Results from the PLCO (Prostate, Lung, Colorectal, and Ovarian) Cancer Screening Trial provide convincing evidence that using chest x-rays to screen for lung cancer does not reduce lung cancer deaths. These results were published in the Journal of the American Medical Association.
Lung cancer is the leading cause of cancer death among both men and women in the United States. The disease is often detected at an advanced, difficult-to-treat stage.
Cancer screening involves the use of tests to detect cancer at an early stage in people who don’t have any symptoms of the disease. For cancers such as breast cancer, colorectal cancer, and cervical cancer, screening has contributed to decreased rates of cancer death. Understandably, there has also been a great deal of interest in whether lung cancer screening with tests such as chest X-rays or computed tomography (CT) scans could reduce lung cancer mortality.
Promising results for low-dose spiral CT were published earlier this year in the New England Journal of Medicine. The National Lung Screening Trial (NLST) enrolled current and former heavy smokers. Study participants were screened with either chest x-rays or low-dose spiral CT. People in the CT group were 20% less likely to die of lung cancer.
The PLCO Cancer Screening Trial compared chest x-rays (every year for four years) to usual care (no screening) among almost 155,000 people between the ages of 55 and 74.
- During the 13 years of the study, there were 1,213 lung cancer deaths in the chest x-ray group and 1,230 in the usual care group. The small difference between the two groups was not statistically significant (could have occurred by chance alone).
These results indicate that annual screening with chest x-ray does not reduce lung cancer mortality.
Although previously reported results from the NLST suggest that low-dose spiral CT screening may provide a benefit among heavy smokers, groups such as the American Cancer Society do not yet recommend CT for lung cancer screening. The results of recent trials will need to be closely reviewed in order to determine how often and for whom screening may be appropriate. Identifying the optimal screening strategy—as well as the groups of people most likely to benefit—is important because screening does carry some risks. False-positive test results, for example, can lead to unnecessary additional workup.
 The National Lung Screening Trial Research Team. Reduced lung-cancer mortality with low-dose computed tomographic screening. New England Journal of Medicine. 2011;365:395-409.
 Oken MM, Hocking WG, Kvale PA et al. Screening by chest radiograph and lung cancer mortality. The Prostate, Lung, Colorectal, and Ovarian (PLCO) Randomized Trial. Journal of the American Medical Association. Early online publication October 26, 2011.
 American Cancer Society. Can non-small cell lung cancer be found early? Last revised September 15, 2011.
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