Increased lung cancer risk in patients with interstitial lung disease and elevated CEA and CA125 serum tumour markers.

BACKGROUND AND OBJECTIVE The aetiology and pathogenesis of interstitial lung disease (ILD) and ILD combined with lung cancer (ILD-CA) are unclear. We aim to investigate serum tumour marker (STM) levels and to explore their predictive and diagnostic value of cancer in ILD. METHODS Fifty-eight patients with ILD-CA, 632 with ILD only and 628 with acute respiratory illness were studied. Serum levels of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), CA125 and neuron-specific enolase (NSE) were measured. RESULTS All STM levels were elevated in ILD-CA compared with ILD group (P < 0.01). CEA and CA125 levels were significantly higher in ILD than in controls (P < 0.01). After adjustment for gender, age and smoking, ILD-CA risk in the CEA and CA125 fourth quartiles was increased compared with the first quartiles (CEA: odds ratio (OR) = 8.7, 95% confidence interval (CI) = 2.0-37.6; CA125: OR = 9.8, 95% CI = 2.3-42.7). Receiver operating characteristic (ROC) curve analysis in patients with ILD-CA showed a cut-off points of 3.99 ng/mL for CEA and 35.00 U/mL for CA125 with sensitivities of 74.6% and 71.9%, specificities 70.4% and 66.1%, and the areas under the curve 0.76 (95% CI = 0.69-0.82) and 0.75 (95% CI = 0.69-0.81), respectively. CONCLUSIONS Serum CEA and CA125 levels are often elevated in ILD patients. The risk of cancer in ILD is increased with an elevation of serum CEA and CA125 levels. Serum CEA and CA125 levels may be a marker of cancer in ILD patients.