Lung cancer is the leading cause of cancer death in the United States and is responsible for more deaths than breast, prostate, and colon cancers combined. Could screening with computed tomography reduce the number of deaths?

Not necessarily, say researchers from Harvard and Mayo Clinic in Rochester, Minn, who determined the long-term effectiveness of CT screening for lung cancer by using data from 1,520 current and former smokers, which was entered into the Lung Cancer Policy model, a simulation model of lung cancer development, screening findings, treatment results, and long-term outcomes.

The researchers interpreted the data and projected that at 6-year follow-up, patients who had undergone five annual screenings had an estimated 37% relative increase in lung cancer detection compared with those who had not been screened. The relative reduction in deaths from lung cancer was 28%, but reduction in all cause mortality was only 4%.

"Our study fills in a piece of the puzzle but does not solve it," says Harvard’s Pamela McMahon, PhD, lead author of the study. "We are hopeful that randomized trials conducted by the National Cancer Institute will show a benefit from screening. But, she adds, “The number-one goal should still be to quit smoking, because it will reduce risk of death from many causes,” not just lung cancer.