Correlation between serum tumor marker levels and connective tissue disease-related interstitial lung disease

Abstract

Objective: The main aims of this study were to explore the relationships between serum tumor markers and connective tissue disease-related interstitial lung disease (CTD-ILD) and to evaluate the clinical value of tumor markers for investigating interstitial lung disease (ILD) in patients with connective tissue disease (CTD). Methods: The study included 235 patients with CTD (90 CTD without ILDs, 145 CTD-ILD). Clinical information and the levels of inflammatory and tumor markers, including carbohydrate antigen (CA) 19–9, CA125, carcinoembryonic antigen (CEA), CA153, and cytokeratin 19 fragments (CYFRA21-1), were obtained in all the patients. Results: A significant difference between CTD with or without ILD and higher levels of tumor markers was observed in the CTD-ILD group, including CA19-9 (p<0.001), CEA (p<0.001), CA153 (p<0.001), and CYFRA21-1 (p<0.001). There was no significant difference in serum tumor marker levels in the various types of CTD (rheumatoid arthritis, systemic lupus erythematosus, Sjogren’s syndrome, inflammatory myositis, systemic sclero-sis, and mixed connective tissue disease). The levels of CA153 [odds ratio (OR)=1.159] and CYFRA21-1 (OR=2.269) were clearly related to the risk of CTD-ILD. The diagnostic value of CA153 [area under receiver operating characteristic curve (AUC)=0.736] and CYFRA21-1 (AUC=0.718) was confirmed for ILDs in CTD patients, at cut-off values of 9.45 U/mL and 2.13 ng/mL, respectively. Conclusion: There is a positive correlation between serum tumor marker levels and CTD-ILD. Higher levels of CA153 and CYFRA21-1 suggest an increased risk of developing ILD and may therefore be useful as biomarkers for detecting CTD-ILD in the clinical setting.