Comparative prognostic value of lactate dehydrogenase and neuron-specific enolase in small-cell lung cancer patients treated with platinum-based chemotherapy.

The influence of pretreatment serum levels of lactate dehydrogenase (LDH) and neuron-specific enolase (NSE) on survival was investigated in a series of 263 consecutive patients with small-cell lung cancer. LDH was elevated in one-half of the patients, NSE in 79%. Both were significantly higher when the disease was considered extensive than when it was limited. The markers were significantly correlated (r= 0.54, P=1.03 x 10(-20)), and both had a significant impact on survival in the univariate analysis. The multivariate survival analysis of the entire population showed that LDH, along with performance status, extent of disease, and albumin, was a more important prognostic factor than NSE. Only when LDH was removed from the model did NSE become an independent prognostic factor. In the separate multivariate survival analyses of limited and extensive disease, LDH remained an independent prognostic factor. For extensive disease, NSE did not even appear in the model when LDH was excluded; for limited stage disease, NSE did become a weak independent prognostic factor when LDH was excluded. In conclusion, LDH, which is less expensive to assay than NSE, is also a stronger independent prognostic factor for small-cell lung cancer and should be part of the initial work-up. In clinical trials, stratification for LDH levels should be considered because of its prognostic weight.