Screening values of carcinoembryonic antigen and cytokeratin 19 fragment for lung cancer in combination with low-dose computed tomography in high-risk populations: Initial and 2-year screening outcomes

Abstract Objectives To assess added screening value of Carcinoembryonic Antigen (CEA) and Cytokeratin 19 Fragment (CYFRA 21-1) in combination with LDCT beyond LDCT alone and likelihood ratio of positive (LHR+) of their combination for lung cancer in high-risk populations with indeterminate and positive LDCT after initial screening and 2-year follow up. Materials and methods LDCT was performed annually at baseline and for 2 years in 634 heavy smokers (>30 pack-years) who were aged 50–70 years, and it was classified as negative, indeterminate, or positive (suspicious for lung cancer). Serum CEA and CYFRA 21-1 were examined and followed with LDCT in the indeterminate and positive LDCT groups and defined as positive with an abnormal level of either CEA or CYFRA 21-1. Results A total of 17 lung cancer cases were diagnosed (9 from initial screening and 8 from follow-up cycles). Seventy and 22 patients had indeterminate and positive baseline LDCT, respectively. Among indeterminate baseline LDCT, the LHR+ for lung cancer diagnosed after initial screening with a positive marker was 6.61 (p = .039) and 1.51 (p = .502) with a negative marker. After 2 years follow up, the LHR+ was 6.31 (p = .004) and 0.86 (p = .677), respectively. Among positive baseline LDCT, the LHR+ for lung cancer diagnosed after initial round with positive and negative markers was 69.44 (p  Conclusions CEA in combination with LDCT significantly increases the value of lung cancer screening compared with using LDCT alone particularly in participants with indeterminate baseline LDCT in both initial and 2-year screening outcomes.