Neuron-specific enolase as a guide to the treatment of small cell lung cancer.

A retrospective evaluation of serial measurements of neuron-specific enolase (NSE) has been performed in 58 patients with small cell lung cancer (SCLC). All 58 patients received first-line chemotherapy and 11 patients received also second-line treatment after relapse. Samples were obtained every 3-4 weeks during treatment before each cycle of chemotherapy and every 6 or 12 weeks during follow-up. NSE values were depicted on semi-logarithmic paper. Fifty-one times a major response (complete or partial remission) was observed and 49 times the NSE level reached a plateau between 3.5-10 ng/ml. The NSE level did not discriminate between a complete or a partial remission. Seven times stable disease was obtained and the NSE level declined but remained above the normal plateau of 3.5-10 ng/ml. On 50 occasions progressive disease was found. In 3 cases progressive disease was due to a histologically-proven non-small cell lung cancer and NSE levels did not change. In only 5 out of the remaining 47 occasions NSE levels were normal at the time of relapse but rose later in 4. On 42 occasions of progressive SCLC an exponential rise of NSE was found, often within the range of 3.5-20 ng/ml. None of 6 patients, who are still incomplete remission for 1-5 years, showed a consistent rise of NSE. Serial measurements of serum NSE, can predict the occurrence of a major response, stable disease and progressive disease outside the brain with a very high accuracy and seem to be at least a useful addition to standard investigational methods to guide the treatment of SCLC.