Value of CT screening for lung cancer unclear

In people at high risk for lung cancer, low-dose CT scanning of the chest may detect early lung cancer, researchers report. However, "its usefulness as a screening tool is limited" because it misses tumors in certain areas of the lung and often falsely identifies harmless spots as being cancerous.

The results have been mixed on the ability of CT scans to spot early lung tumors, when cure rates following surgery are excellent, note Dr. R. MacRedmond from Beaumont Hospital in Dublin, Ireland, and colleagues in the medical journal Thorax.

The team reports on their study of CT scanning performed over a 2-year period in 449 individuals at high risk for lung cancer, with follow-up for tumors greater than 1 centimeter in diameter.

Such nodules were identified in 111 subjects, and 3 were found to be operable lung tumors. Three other cancers detected in the study were located in the center of the lung and were not amenable to surgery.

"The overall...rates of lung cancer detection were low," MacRedmond and colleagues report.

While 19 percent of subjects quit smoking during the 2-year study period - a rate higher than that observed in the general population - 60.8 percent continued to smoke.

The authors note that CT screening for lung cancer is expensive. Costs "may prove prohibitive, particularly when over half of the screening population continue to smoke" - and a reduction in death rates has yet to be proven.

The author of a related editorial maintains that the jury is still out on the value of CT scans for lung cancer screening. "Data from the randomized controlled trials currently underway are awaited," writes Dr. F. V. Gleeson of Churchill Hospital in Oxford, UK, including the results from the National Lung Screening Trial. This "huge" trial has randomly assigned 50,000 adults to CT scans or standard X-rays.

SOURCE: Thorax, January 2006.