Choice of serum tumor markers in patients with small cell lung cancer: progastrin-releasing peptide, neuron-specific enolase, and carcinoembryonic antigen

Abstract Lung cancer is a leading cause of cancer-related deaths worldwide. It mainly consists of 2 histological types: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC, including squamous cell carcinoma and adenocarcinoma). The present study aimed to assess the role of serum progastrin-releasing peptide (ProGRP), neuron-specific enolase (NSE), and carcinoembryonic antigen (CEA) and their combinations in the histological diagnosis of lung cancer (specially SCLC), which is of great importance for the initiation of treatment and prognostic implications. Serum ProGRP, NSE, and CEA were determined by the electrochemiluminescence immunoassay (ECLIA) in 66 patients with SCLC, 73 with adenocarcinoma, 44 with squamous cell carcinoma, 45 with non-malignant pulmonary diseases, and 50 healthy controls. Receiver operating characteristic curves were constructed to compare the predictive ability of each biochemical marker and their combined detection models to discriminate among the patients with lung cancers of different histological groups, benign pulmonary diseases and healthy individuals. In the ECLIA detection system, ProGRP showed the sensitivity and specificity for SCLC diagnosis were 71.2% and 91.1% to 93.2%, respectively. Among the markers, the largest area under the ROCs was for ProGRP in discriminating SCLC from benign pulmonary diseases, squamous cell carcinoma and adenocarcinoma (0.815, 0.859, and 0.835, respectively), which indicated that ProGRP was the most efficient marker for identifying SCLC. Besides, ProGRP and NSE exhibited almost equivalent diagnostic performance in discriminating SCLC from benign diseases. As for squamous cell carcinoma, we recommended proGRP, while for adenocarcinoma, the combination of proGRP and CEA was preferred. Remarkably, when ProGRP ⩽ 66 pg/mL, CEA was of great value in diagnosing SCLC and adenocarcinoma. If CEA ⩽ 5 ng/mL, the patient was at higher risk for SCLC, whereas the patient was more likely to be diagnosed with adenocarcinoma. Our study provided promising information about the diagnostic values of serum ProGRP, NSE, CEA in distinguishing SCLC from benign pulmonary diseases and NSCLC, which was of crucial clinical significance in the early diagnosis and therapy of SCLC.