Prognosis of non-small-cell lung cancer patients with positive pleural lavage cytology

OBJECTIVES: Positive pleural lavage cytology (PLC) is considered as a precursor condition of pleural dissemination (PD) or malignant pleural effusion (PE), and one of the poor prognostic factors in surgically resected non-small-cell lung cancer (NSCLC) patients. Although PD and PE are classified as M1a, PLC does not contribute to the tumour, node and metastasis (TNM) classification of the Union Internationale Contre le Cancer. This study aimed to evaluate the prognostic effect of positive PLC status in surgically resected NSCLC patients compared with PD and/or PE. We also aimed to consider the contribution of positive PLC status to the TNM classification. METHODS: We reviewed 1572 consecutive patients with completely resected NSCLC, and analysed the relationship between PLC status, other clinicopathological factors and prognosis. The survival rates of 45 patients with PD and/or PE were also investigated. RESULTS: Positive preresection PLC (pre-PLC) status was observed in 56 patients. Pre-PLC status was significantly associated with other clinicopathological factors. Positive pre-PLC patients exhibited a worse 5-year overall survival (50.6%) compared with negative pre-PLC patients (78.0%), but better survival than PD and/or PE patients (21.0%). Prognosis of positive pre-PLC patients was equal to that of pT3, negative pre-PLC patients; survival equality was observed when patients were stratified according to pN0, pN1 and pN2. CONCLUSIONS: Positive pre-PLC had the significant prognostic effect in surgically resected NSCLC patients. However, it is not a contraindication for surgical resection, unlike PD and/or PE. Our data suggest that positive pre-PLC should be classified as pT3 in next TNM classification.