Serum biomarkers of non-neuron-endocrine origin in small-cell lung cancer: a 16-year study on carcinoembryonic antigen, tissue polypeptide antigen and lactate dehydrogenase

Background: Biomarkers of non-neuron-endocrine origin are measured only occasionally in the sera of patients with small-cell lung cancer (SCLC). An exception to this rule is carcinoembryonic antigen (CEA), for which, however, there is no consistent evidence. Based on such a premise, we decided to review the Cuneo Lung Cancer Study Group 16-year-experience with non-neuron-endocrine markers in SCLC. Methods: a total of 619 CEA, 621 tissue polypeptide antigen (TPA), and 616 lactate dehydrogenase (LDH) serum assays were obtained from 160 consecutive SCLC at diagnosis, during, and after treatment. Demographic, clinical, laboratory, and tumoral correlates were also available for another 25 pretreatment and 14 posttreatment variables. Results: bivariate correlation analyses showed that LDH and TPA were significantly related to each other, and both of them were also correlated with disease extent, and treatment response. LDH correlation indexes were higher than that of TPA, especially those regarding the parameters of disease extent. CEA was correlated only with the category of treatment response. Receiver-operating characteristic (ROC) analysis confirmed the correlation between stage disease at diagnosis and both LDH (P = 0.000) and TPA (P = 0.002), while the treatment failure was better recognized by TPA (P = 0.000). In univariate analysis, both LDH and TPA were correlated with survival (P = 0.000 and 0.092, respectively); however, only LDH remained significant in multivariate analysis (P = 0.012). Conclusions: the evidence from this study does not suggest a routine CEA test in SCLC. LDH remains particularly useful and it should be kept in use. Finally, data on TPA is insufficient to advocate its systematic use in this type of malignancy. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.