Low-dose computed tomography (LDCT) scans have emerged as an effective screening tool for lung cancer, especially in high-risk patients. However, the method may have a significant rate of overdiagnosis, that is, detection of cancers that would not have caused any symptoms during the patient’s lifetime. These cancers may be slow growing or otherwise clinically insignificant. Overdiagnosis can lead to unnecessary treatment, generating significant cost and anxiety and risking medical complications. A large study comparing LDCT screening with another screening method, chest radiography, estimated that 18.5% of the lung cancer cases detected represented overdiagnoses. For cases of non-small cell lung cancer (NSCLC) and bronchioalveolar carcinoma (cancer of the air sacs), estimated overdiagnosis rates were 22.5% and 78.9%, respectively.