The latest word on lung cancer screening was just published in a recent New England Journal of Medicine. In this trial, participants at high risk of getting lung cancer were given either annual chest x-rays or spiral CT scans for three years. There was an annual analysis of new lung cancer cases and deaths in each group.
At the end of the study the results were revealed: those who had undergone regular CT scanning had a 20% reduction in lung cancer mortality. (See graphs below for details.) How can we put this in perspective; is this a game-changer in the cancer detection field?
First of all, the absolute number of lung cancer cases in each group was small, only slightly more than 1% of the participants in each group. With a 20% difference in mortality hundreds of people would need to be screened to reduce mortality by one person. No attempt was made in this trial to assess the cost of saving that life.