Impact of Positive Pleural Lavage Cytology for Each Stage of Non-Small Cell Lung Cancer Patients.

BACKGROUND: Positive pre-resection pleural lavage cytology (PLC+) is a poor prognostic factor of non-small cell lung cancer (NSCLC). We evaluated the prognosis of PLC+ for the different pathological stages (p-stage) of NSCLC.

METHODS: Retrospective analysis of all staged 1293 patients who underwent curative resection for NSCLC to evaluate the impact of PLC+ on survival, specifically in p-stage I NSCLC patients. The survival rate between patients with and without PLC+ was compared using the Kaplan-Meier method with the log-rank test for comparison.

RESULTS: PLC+ was identified in 50 of the 1293 patients (3.9%) and was correlated to lymph node metastasis (p<0.001); a pathological tumor size >3 cm (p=0.033); presence of pleural invasion (p<0.001); and adenocarcinoma (p=0.038). In patients with PLC+, the 5-year disease-free survival (DFS) was 31.1%, compared to 75.7% for those with a negative PLC (PLC-) (p<0.001). On multivariate analysis, the PLC+ status was an independent prognostic factor of DFS (hazard ratio 1.70, p=0.013). Among the 818 p-stage I NSCLC patients, PLC+ was identified in 22, with a 5-year DFS of 40.4%. The prognosis of p-stage I NSCLC patients with PLC+ was equal to that of p-stage IIIA NSCLC patients with PLC- (5-year DFS, 40.4% and 39.0%).

CONCLUSIONS: PLC is an independent prognostic factor of early stage NSCLC. Therefore, it may be appropriate to up-stage NSCLC diagnosis in the presence of PLC+, especially for p-stage I.