DO NEURON-SPECIFIC ENOLASE LEVELS DISCRIMINATE BETWEEN SMALL-CELL LUNG-CANCER AND MEDIASTINAL TUMORS

The capacity of pretherapeutically assessed neuron-specific enolase (N SE) to differentiate between small cell lung cancer (SCLC) and mediast inal tumors was investigated retrospectively in a series of 320 patien ts. NSE was found to be increased in 95/130 (73.1%) patients with SCLC , in 4/62 (6.5%) patients with Hodgkin's disease, in 10/58 (17.2%) pat ients with non-Hodgkin's lymphoma, in 5/16 (31.3%) patients with terat oma, and in 6/54 (11.1%) patients with thymoma. The cut-off value, def ined as the 95% percentile of a reference population suffering from be nign pulmonary disorders (n = 192), was set at 13.8 ng/ml. When this d iscrimination level was increased to 26.4 ng/ml, which corresponds to a 95% specificity versus the total group with mediastinal tumors, SCLC was recognized with a detection rate of only 49.2%. In conclusion, in creased NSE concentrations in a patient with a hilar mass and/or media stinal widening on X-ray are not always diagnostic of SCLC due to the high rate of elevated NSE values associated with mediastinal tumors. H owever, in a patient who presents with a hilar mass and a high NSE lev el, bronchoscopy is always indicated to obtain adequate specimens for histology in order to plan an appropriate therapeutic regimen.