Abstract: ObjectiveTo investigate the levels of tumor markers carcino-embryonic antigen (CEA), neuron-specific enolase (NSE), cytokeratin-19 fragment (CYFRA21-1) and pro-gastrin-releasing peptide (ProGRP) in the peripheral blood of lung cancer patients before and after chemotherapy and their correlations with recent efficacy of chemotherapy. MethodsA total of 80 lung cancer patients were randomly selected who received chemotherapy for at least two durations. Their levels of CEA, NSE, CYFRA21-1 and ProGRP in the peripheral blood were detected before and after chemotherapy. Their relationship with clinical characteristics, chemotherapy efficacy, and prognosis was discussed. ResultsThe squamous cell carcinoma group showed a remarkably higher level of serum CYFRA 21-1 than other group (P<0.05). Although the level of CEA in the adenocarcinoma group was higher than those in other groups, there was no statistical difference between each group (P>0.05). Meanwhile, the small cell lung cancer group produced significantly higher levels of NSE and ProGRP than the NSCLC group (P<0.05)．Remarkably better clinical efficacy and prognosis were found in patients with decreased levels of tumor markers, compared with those with increased levels (P<0.05). ConclusionsThe levels of CEA, NSE, CYFRA21-1 and ProGRP can be used as the important indicators for evaluating the efficacy of lung cancer chemotherapy with specific pathological types.