Abstract: Objective To observe the effects of thoracic cavity perfusion chemotherapy on cytokeratin 19 fragment （Cyfra21-1），CA125，carcinoembryonic antigen（CEA），and neuron-specific enolase（NSE） in patients with non-small cell lung cancer and malignant pleural effusion. Methods A total of 70 patients with non-small cell lung cancer and malignant pleural effusion were subjected to closed drainage of the thoracic cavity using a central venous catheter，and cisplatin reperfusion of the thoracic cavity. Chemiluminescence immunoassay was performed before and after these procedures in order to monitor levels of serum Cyfra21-1，CA125，CEA，and NSE. Curative efficacy was measured using WHO standards for purulent cancer exudate，and adverse reactions were observed. Results The total efficacy rate was 75.71%，and the disease control rate was 85.71%. Levels of CA125，serum Cyfra21-1，CEA，and NSE were lower after pleural reperfusion than before（P<0.001）. The main adverse reactions were gastrointestinal reactions and bone marrow suppression （degree I-II events）；no damage to liver or kidneys was observed. Conclusion Pleural infusion chemotherapy in the treatment of non-small cell lung cancer pleural effusion can effectively control pleural effusion and decrease the levels of serum Cyfra21-1，CA125， CEA，and NSE. This therapy may also help clinicians predict sensitivity to platinum-based chemotherapy in patients receiving systemic treatment.

Key words: Lung neoplasm, Malignant pleural effusion, Pleural infusion chemotherapy, Cytokeratin 19 fragment, CA125, Carcinoem-bryonic antigen, Neuron-specific enolase