The goal of this project is to understand the morbidity and mortality associated with detection of a significant incidental finding (SIF) on low-dose CT lung screening. SIF detection may be associated with early diagnosis of extra-pulmonary cancers and other conditions that benefit the patient or with the discovery of benign findings that generates unneeded and potentially harmful medical procedures. The results from this research will provide evidence for the development of practice guidelines to address SIFs detected at LDCT lung screening.