BACKGROUND The measurement of carbohydrate antigen 19-9 (CA 19-9) is recommended for the diagnosis and follow-up of pancreatic cancer. However, increased CA 19-9 has also been reported in patients with various benign diseases of the lung. We aimed to elucidate the pulmonary radiographic abnormalities and laboratory results associated with increased concentrations of CA 19-9.

METHODS This study was performed using a case-controlled design. Cases included all participants in a cancer screening program who had an increased CA 19-9 concentration (>37 U/mL), but without a diagnosis of malignancy. Age- and sex-matched participants with normal CA 19-9 levels were enrolled as controls. Laboratory results and radiographic features were compared.

RESULTS In total, 119 participants with increased CA 19-9 concentrations and 476 controls were included. A higher erythrocyte sedimentation rate (ESR) [adjusted odd ratio (aOR), 1.03; 95% confidence interval (CI), 1.01-1.05], higher hemoglobin A(1c) (HbA(1c)) (aOR, 1.28; 95% CI, 1.05-1.56), bronchiectasis (aOR, 2.48; 95% CI, 1.22-5.02), bronchiolitis (aOR, 3.93; 95% CI, 1.88-8.22), emphysema (aOR, 2.67; 95% CI, 1.32-5.40), and interstitial fibrosis (aOR, 10.62; 95% CI, 2.03-55.44) were independent factors for increased CA 19-9.

CONCLUSIONS CA 19-9 concentrations, as well as increased ESR and HbA(1c), can be increased in patients with various lung abnormalities.