CT screening for lung cancer is a complex undertaking requiring specifications of all of its components. This includes questions as to who should be screened, how frequently screening should be performed, and an optimal regimen of screening. The regimen of screened defines who requires further workup during the year the screening is performed in addition to the specification of the CT acquisition parameters, how the readings are performed, and the results communicated to the participants being screened. In addition to looking for suspicious pulmonary nodules, the CT scan also shows the heart, mediastinum thyroid, and the organs in the upper abdomen. The recommendations for abnormal findings in all these organs and the workup also need to be interpreted in light of the fact that they are found in asymptomatic people at risk of lung cancer and not that they presented for clinical care because of symptoms. This report provides the International Early Lung Cancer Action Program (I-ELCAP) protocol for screening and also provides the references that provide the basis for the protocol. This protocol has been continually updated in light of advancing CT and diagnostic technology and knowledge that has emerged as a result of screening, particularly large databases that have been developed.
