Lung cancer is the leading cause of cancer-related deaths in the united states. researchers examined the idea of testing all medicare-enrolled heavy smokers for lung cancer with a computed tomography (ct) scan every year. in this population, the lifetime chance of developing lung cancer is high. in any given year, approximately 3% of heavy smokers develop lung cancer. the ct scan positively identifies lung cancer 89% of the time, and it gives a negative result for 93% of individuals who do not have lung cancer.