[Clinical evaluation of serum carbohydrate antigen 19-9 in carcinoma of the lung--a comparison with carcinoembryonic antigen].

Serum levels of carbohydrate antigen 19-9 (CA 19-9) were measured in 235 untreated patients with lung cancer, 20 patients with benign pulmonary disease and 39 healthy controls. In almost all these patients, carcinoembryonic antigen (CEA) was determined at the same time. The positivity of CA 19-9 in lung cancer patients was significantly higher than in those with benign pulmonary disease (30.2% vs. 5%: P less than 0.05). With regard to histological types of lung cancer cases, the positivity of CA 19-9 in adenocarcinoma cases was higher than that in cases of squamous cell carcinoma (39.6% vs. 16.4% : P less than 0.01). With regard to clinical stages of lung cancer positivity of CA 19-9 in stage IV (37.9% vs. 10.3% : P less than 0.01) or stage III (30.3% vs. 10.3% : P less than 0.05) was significantly higher than in stage I. Sensitivity, specificity and accuracy in the detection of lung cancer were 31%, 95%, and 36% for CA 19-9, and 46%, 80% and 49% for CEA, respectively. Combined evaluation with CA 19-9 and CEA gave the highest specificity (98%) when both were measured, and the highest sensitivity (55%) when at least one was measured. Combined assessment of CA 19-9 and CEA improved the measurement of each one in the detection of lung cancer.