Serum neuron-specific enolase as a marker of small-cell carcinoma of the esophagus.

We monitored the changes in serum neuron-specific enolase (NSE) level in two patients with esophageal small-cell carcinoma (SCC) during the course of treatment by chemotherapy or surgery, with radiation. Serum NSE levels at diagnosis were 18.5 and 58.0 ng/ml. In both cases, after treatment the serum NSE level decreased to within normal range (less than 10.0 ng/ml), concurrent with reduction in the size of the tumor. However, with relapse of the disease, the serum NSE increased to 24.3 and 200.0 ng/ml, respectively. One patient died of lung and skin metastases 4 months after surgery; the other, who developed brain metastasis, was treated again with chemotherapy by the same regimen. The serum NSE level decreased to 13.0 ng/ml, and the symptoms improved. These results indicate that there is a correlation between serum NSE level and remission or relapse of the disease after treatment in patients with SCC of the esophagus, as with SCC of the lung.