Thoracic and Extrathoracic Malignancies in Lung Cancer Screening Patients With Histories of Malignancy

PurposeThe objective of this study was to assess whether a history of malignancy affects the incidence of extrathoracic malignancies and lung cancer in patients undergoing CT lung cancer screening (LCS).MethodsAll patients who underwent a LCS CT between June 2014 and August 2018 in a single health care system were included. History of prior nonskin malignancy was extracted from billing records. Subsequent diagnoses of malignancy were extracted from clinical pathology reports. Risk for subsequent malignancy was compared between patients with and those without prior malignancy and evaluated using multivariate logistic regression including age and history of malignancy.ResultsA total of 5,835 LCS CT studies were included, and 1,243 (21%) were performed on patients with diagnoses of malignancy before CT. For the 4,592 scans performed on patients without histories of malignancy, 87 patients (1.9%) were diagnosed with lung cancer and 68 (1.5%) were diagnosed with nonlung malignancies in the following year. Among patients with histories of malignancy, 17 (1.4%) were diagnosed with lung cancer, and 25 (2%) were diagnosed with nonlung malignancies. Logistic regression for subsequent diagnosis of malignancy (including lung cancer) demonstrated age to be predictive, with an odds ratio of 1.6 per decade (P < .0001); history of malignancy was not predictive of subsequent malignancy (P = .50).ConclusionsPatients with histories of malignancy referred for LCS have a similar risk for developing lung cancers and extrathoracic malignancies as patients without histories of malignancy. Patients with histories of malignancy who are believed by their referring providers to be at low risk for metastasis should not be excluded from LCS.