Cytokeratin 19 fragment CYFRA 21-1 compared with carcinoembryonic antigen, squamous cell carcinoma antigen and neuron-specific enolase in lung cancer. Results of an international multicentre study.

The diagnostic value of the water-soluble cytokeratin 19 fragment CYFRA 21-1 in lung cancer was assessed in comparison with carcinoembryonic antigen, squamous cell carcinoma antigen, and neuron-specific enolase. The cut-off value, defined as 95% specificity versus a group of 526 patients suffering from benign chest diseases, was set at 3.3 micrograms/l for cytokeratin 19 fragment CYFRA 21-1 (carcinoembryonic antigen: 7.8 micrograms/l, squamous cell carcinoma antigen: 1.9 micrograms/l, neuron-specific enolase: 13.7 micrograms/l). Elevated pretreatment cytokeratin 19 fragment CYFRA 21-1 concentrations were recorded: in 112 of 244 (46%) patients with all histological types of lung cancer (carcinoembryonic antigen: 32%, squamous cell carcinoma antigen: 25%, neuron-specific enolase: 28%), in 89 of 177 (50%) patients with non-small cell lung cancer (carcinoembryonic antigen: 33%, squamous cell carcinoma antigen: 24%, neuron-specific enolase: 12%), in 47 of 81 (58%) patients with squamous cell carcinoma (carcinoembryonic antigen: 23%, squamous cell carcinoma antigen: 32%, neuron-specific enolase: 14%), in 27 of 63 (42%) patients with adenocarcinoma (carcinoembryonic antigen: 44%, squamous cell carcinoma antigen: 14%, neuron-specific enolase: 9%), in 15 of 33 (45%) patients with other non-small cell lung cancer (carcinoembryonic antigen: 36%, squamous cell carcinoma antigen: 24%, neuron-specific enolase: 14%), and in 20 of 55 (36%) patients with small cell lung cancer (carcinoembryonic antigen: 32%, neuron-specific enolase: 77%). Three of 12 patients with undefined histological type showed cytokeratin 19 fragment CYFRA 21-1 elevations. The best performance in terms of sensitivity and diagnostic accuracy was attained with the cytokeratin 19 fragment CYFRA 21-1 test in squamous cell carcinoma. In small cell lung cancer neuron-specific enolase was confirmed to be superior to the other markers. Cytokeratin 19 fragment CYFRA 21-1 concentrations increased with the extent of the malignant disease in non-small cell lung cancer. The positivity rate of cytokeratin 19 fragment CYFRA 21-1 in tumour stage TNM I was only 23% (carcinoembryonic antigen: 23%, squamous cell carcinoma antigen: 14%), i.e. the markers under study cannot be used for the diagnosis of early stage disease. Cytokeratin 19 fragment CYFRA 21-1 differentiated significantly between squamous cell carcinoma and the other histological types (p < 0.01). In addition, cytokeratin 19 fragment CYFRA 21-1 distinguished significantly the operable group TNM I-IIIa from inoperable TNM IIIb-IV (p < 0.05), but not TNM IIIa from IIIb. Out of 177 patients with non-small cell lung cancer, 90 individuals were monitored after surgery.(ABSTRACT TRUNCATED AT 400 WORDS)