Lung cancer. 2: screening and early diagnosis of lung cancer.

Technical developments in spiral CT scanning mean that considerably smaller lung cancers can now be identified than with previous methods of detection. Only time will tell whether this enhanced capability will result in a reduction in the number of deaths from lung cancer. The implications and problems of screening for lung cancer are discussed. Screening implies a careful refinement of a range of clinical activities that must be routinely delivered in a carefully coordinated fashion to allow for the possibility of improved outcome. Critical analyses of the nuances of this process are essential if the field is to move forward.