January 10, 2006

Value of CT screening for lung cancer unclear

NEW YORK (Reuters Health) - 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

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.