CARCINOEMBRYONIC ANTIGEN, TISSUE POLYPEPTIDE ANTIGEN AND NEURON-SPECIFIC ENOLASE PLEURAL LEVELS USED TO CLASSIFY SMALL-CELL AND NON-SMALL-CELL LUNG-CANCER PATIENTS BY DISCRIMINANT-ANALYSIS

The classification of lung cancer into small-cell lung cancer (SCLC) a nd non-small-cell lung cancer (NSCLC) is essential for disease prognos is and treatment. For this purpose, we have tried to optimize the use of three tumour markers determined on pleural effusions, to differenti ate SCLC from NSCLC by means of a canonic variable, generated by discr iminant analysis, including subjects with histologically proven lung c ancer. Discriminant analysis was performed by using carcinoembryonic a ntigen, neuron-specific enolase and tissue polypeptide antigen pleural levels, determined in 65 consecutive and unselected patients, histolo gically classified as 49 NSCLC and 16 SCLC. To validate the formula ge nerated, a control group of 37 lung cancer patients (10 SCLC and 27 NS CLC), enrolled subsequently, was employed. Applying the discriminant a nalysis to SCLC and NSCLC patients a good classification was obtained (92% rate of correct classification). The aforementioned formula, appl ied to the validation group, showed a 92% rate of correct classificati on. This method, which is rapid, inexpensive and routinely applicable to malignant pleural effusions, may be reliably used to classify lung cancer patients.