Background:The propose was to recognize risk factors of malignant pleural effusion (MPE) recurrence in patients with symptomatic M1a non-small cell lung cancer (NSCLC). Methods: All patients with NSCLC and MPE submitted to pleural palliative procedures were enrolled in a prospective study. Group I contained patients who had pleural recurrence, and Group II with no pleural recurrence. Prognostic factors for pleural recurrence were identified by univariable analysis, using Fisher's exact test for categorical variables and Student's t test for quantitative variables. Afterwards the significant variables were entered into a multivariable logistic regression analysis (with P<0.05 considered significant).Receiver operating characteristics (ROC) analysis determined the cutoff points for continuous variables. Results: A total of 82 patients were included in the analysis. There were 15 patients (18.3%) in Group I and 67 patients (81.7%) in Group II. Univariable analysis regarding factors affecting postoperative recurrence was: adenosine deaminase concentration in pleural fluid <16 mg/dL (P=0.04), albumin concentration in pleural fluid <2.4 mg/dL (P=0.03), administration of second-line palliative chemotherapy (P=0.018) and type of procedure [therapeutic pleural aspiration (TPA)] (P=0.023). At the multivariable analysis, only the type of procedure (TPA) (P=0.031) was identified as independent predictor of recurrence. Conclusions:The identification of this factor may assist the choice of the optimal palliative technique; at the first episode of MPE in NSCLC patients and definitive procedure as pleurodesis or indwelling pleural catheter are recommended.