Among people with a history of heavy smoking, screening with low-dose helical computed tomography (spiral CT) scans reduced lung cancer mortality by 20%. These results were published in the New England Journal of Medicine.
Lung cancer is the leading cause of cancer death among both men and women in the United States. Each year, an estimated 86,000 men and 71,000 women die of the disease. Other common cancers—such as prostate cancer and breast cancer—kill far fewer people: each year there are roughly 32,000 prostate cancer deaths and 40,000 breast cancer deaths in the U.S.
Avoidance of tobacco smoke offers the best hope for reducing lung cancer mortality. Early detection of lung cancer among people at high risk of the disease is also important, but previous studies of potential screening tests such as chest X-rays found no benefit from screening.
Spiral CT scans use X-rays to obtain a multiple-image scan of the entire chest. To compare screening with spiral CT to screening with standard chest X-ray, researchers conducted a study among more than 53,000 current and former heavy smokers between the ages of 55 and 74. Study participants received three annual screens with either spiral CT or chest X-ray.
Preliminary results from this study were released by the National Cancer Institute in November, 2010, but the current publication provides more detailed findings.
- There were 20% fewer lung cancer deaths among people screened with CT than among people screened with chest X-ray: the number of lung cancer deaths per 100,000 people per year was 247 in the spiral CT group and 309 in the chest X-ray group.
- All-cause mortality (death from any cause, including lung cancer) was reduced by 7% among patients who underwent CT screening.
- False-positive results were more common in the CT group than in the chest X-ray group. A false-positive result suggests that cancer is present when the person is actually cancer-free. Complications from the workup of positive tests, however, were uncommon. False-positive results were typically confirmed by additional imaging rather than by invasive tests such as bronchoscopy or needle biopsy.
These results suggest that among people at high risk of lung cancer as a result of long-term and/or heavy smoking, screening with spiral CT can reduce the number of lung cancer deaths. Groups such as the American Society of Clinical Oncology are now considering what screening guidelines might be warranted based on these results.
 The National Lung Screening Trial Research Team. Reduced lung-cancer mortality with low-dose computed tomographic screening. New England Journal of Medicine. Early online publication June 29, 2011.