Clinical value of CYFRA 21.1, carcinoembryonic antigen, neurone-specific enolase, tissue polypeptide specific antigen and tissue polypeptide antigen in the diagnosis of lung cancer

In this study we looked at what useful information cytokeratin fragment detected by antibodies BM 19-21 and KS 19-1 (CYFRA 21.1), carcinoembryonic antigen (CEA), neurone-specific enolase (NSE), tissue polypeptide specific antigen (TPS), and tissue polypeptide antigen (TPA) gave when measured prospectively. All patients who were suspected of having lung cancer and who underwent diagnostic bronchoscopy in this hospital between July 1994 and May 1995 were included in the study. Of 184 patients, 87 were subsequently found to have intrathoracic malignancy, 93 were found to have benign lung disease and four were lost to follow-up. CYFRA 21.1 was the most efficient marker in differentiating benign from malignant disease, with a sensitivity of 54% and a positive predictive value of 96%. Thirty seven patients who had a negative bronchoscopy subsequently turned out to have malignant disease. Either CYFRA 21.1 or CEA was elevated in 26 (70%) of such patients. Multivariate analysis showed that only CYFRA 21.1 and CEA contributed significantly to the discriminatory power of the data. We conclude that measurement of cytokeratin fragment detected by antibodies BM 19-21 and KS 19-1 and carcinoembryonic antigen at the time of bronchoscopy significantly increased the diagnostic yield in this population and was especially useful in those patients in whom tumour biopsy was not possible at bronchoscopy.