Bronchoalveolar lavage fluid level of carcinoembryonic antigen in the diagnosis of peripheral lung cancer.

: The objective of this study was to verify whether the assay of carcinoembryonic antigen (CEA) in bronchoalveolar lavage fluid (BALF) can increase the sensitivity and specificity of serum CEA for the diagnosis of lung cancer. We examined 72 subjects, 53 males and 19 females, 18 affected with peripheral lung cancer (10 adenocarcinoma, 6 squamous cell carcinoma, 1 small cell lung cancer, 1 adenosquamous carcinoma), 19 with acute pneumonia, 14 with chronic obstructive pulmonary disease (COPD), 6 with interstitial lung disease (ILD), and 15 healthy subjects. CEA was assayed in blood and in BALF using microparticle enzyme immunoassay (MEIA) (IMX Abbott). The mean serum CEA value in the lung cancer group did not differ from that in each group of non-neoplastic subjects, neither was it different from that in healthy subjects. The mean BALF CEA in patients with lung cancer, pneumonia, and COPD was significantly increased compared with that in healthy subjects, whereas there was no difference between the three groups of patients. The ratio of BALF CEA was not significantly different in the three groups of patients. There were no differences according to the histological type of the tumour (adenocarcinoma or squamous cell carcinoma). Based on the results in healthy subjects, the upper limits of normal were defined for serum CEA, BALF CEA, and CEA/albumin ratio. Thus, the sensitivity of BALF CEA in detecting lung cancer (50%) was higher than that of serum CEA (33%), although clinically not useful. In addition, BALF CEA had only 59% specificity compared to 100% of serum CEA. The diagnostic accuracy was 79% for serum CEA and 56% for BALF CEA.(ABSTRACT TRUNCATED AT 250 WORDS)