Significance of serum pro-gastrin-releasing peptide as a predictor of relapse of small cell lung cancer: comparative evaluation with neuron-specific enolase and carcinoembryonic antigen

Neuron-specific enolase (NSE) and carcinoembryonic antigen (CEX) have been reported to be useful markers for staging, monitoring treatment, and predic ting relapse in patients with small cell lung cancer (SCLC). Recently, pro- gastrin-releasing peptide (Pro-GRP) became available as a sensitive, specif ic, and reliable tumor marker for patients with SCLC. The aim of this study is to determine the most useful tumor marker to detect the relapse of SCLC . Furthermore, we analyzed the relationship between tumor markers at relaps e and survival from relapse or response to salvage chemotherapy. Medical re cords were reviewed to obtain serum levels of Pro-GRP, NSE, and CEA before and after the initial chemotherapy, and at relapse. Consecutive 66 patients with SCLC, with an objective response and confirmed relapse treated at the National Cancer Center Hospital East, were analyzed in this study. The per centages of patients whose tumor marker level were elevated before treatmen t, decreased after the treatment, and increased again at relapse were 67% ( 95% CI, 55-78) for Pro-GRP, 20% (10-29) for NSE, and 38% (26-50) for CEA. M ultivariate analysis indicated that poor performance status before initial treatment and elevated serum levels of lactate dehydrogenase at relapse wer e poor prognostic factors for patients with recurrent SCLC (P < 0.005). Non e of the serum levels of Pro-GRP, NSE, and CEA at relapse was a significant prognostic factor and associated with an objective response to salvage che motherapy. The present study demonstrated that serum levels of Pro-GRP refl ect the disease course of patients with SCLC most accurately. (C) 2000 Else vier Science ireland Ltd. All rights reserved.