Tumour markers for prediction of survival and monitoring of remission in small cell lung cancer.
Levels of the tumour markers neurone specific enolase (NSE), lactate dehydrogenase (LDH), chromogranin A (ChrA) and carcinoembryonic antigen (CEA) were measured in serum taken at presentation and during treatment, remission and relapse from 154 patients who received chemotherapy for small cell lung cancer at a single centre over a 6 year period. At presentation NSE was the most frequently elevated marker, being raised in 81% of patients and significantly higher in extensive as opposed to limited disease, as were LDH and ChrA. The response rate to therapy was best correlated with presentation level of ChrA, being 79% for those whose levels were within twice the upper limit of normal and 51% above (P < 0.01). Multivariate regression analysis showed NSE, performance status and albumin at presentation to be the best independent predictors of survival. Patients with NSE below twice the upper limit of normal, Karnofsky performance status of 80 or above and albumin 35 g l-1 or above had a median survival of 15 months with 25% alive at 2 years, whilst those with NSE above twice normal, Karnofsky below 80 and albumin less that 35 g l-1 had all died by 8 months. Changes in marker levels during therapy were of low predictive value for outcome although the finding of rising NSE during chemotherapy after an initial fall correlated with significantly reduced duration of remission. There was a strong inverse correlation between the NSE level at the time of response and duration of remission (P < 0.0001). Prediction of relapse was most reliable with ChrA, 52% of patients having rising levels before clinical evidence of disease recurrence.