SERUM TUMOR-MARKERS IN NONSMALL CELL LUNG-CANCER - A COMPARATIVE-ANALYSIS

Background. The role of serum tumor markers in non-small cell lung can cer (NSCLC) remains undefined. New proposed markers have seldom been r igorously compared with existing standards. The authors prospectively compared the performance of three new monoclonal antibodies (MoAb) (5E 8, 5C7, and 1F10) with the established serum markers carcinoembryonic antigen (CEA) and squamous cell carcinoma antigen (SCC). Methods. The cohort consisted of 45 consecutive outpatients with newly diagnosed NS CLC. Control subjects were 38 outpatients with non-neoplastic chronic pulmonary diseases. Blood from each patient and control subject was as sayed for all five tumor markers. An enzyme linked immunosorbent assay (ELISA) was used to determine 5E8, 5C7, and 1F10 reactivity. Commerci ally available kits were used to measure SCC by radioimmunoassay and C EA by ELISA. Individual and combinations of tumor markers were compare d in terms of sensitivity, specificity, and accuracy for NSCLC diagnos is. Results. 5E8 plus 5C7 plus 1F10 significantly surpassed SCC plus C EA in terms of sensitivity (P < 0.05) and proved the most accurate mar ker combination. Among single markers, 5E8 was most specific, 5C7 most sensitive, and 5C7 and 1F10 each most accurate, but differences from CEA alone were not significant. Subgroup analysis by histologic type a nd stage demonstrated similar findings, and marker combinations yielde d little additional diagnostic benefit. Conclusions. 5E8, 5C7, and 1F1 0 performed marginally better than did CEA and SCC in patients with ne wly diagnosed NSCLC. Many limitations apply in defining a clinical nic he for these tumor markers in NSCLC, although 5E8, 5C7, and 1F10 previ ously have demonstrated a modest prognostic value. An adjunctive role in a few specific clinical contexts remains possible.