We previously reported that cancer cells may be detected through pleural lavage cytology (PLC). In this study, we sought to re-examine the prognostic significance of the PLC status based on an extended dataset with an additional follow-up period. Pleural lavage following thoracotomy was cytologically examined in 1,317 consecutive patients who were diagnosed with NSCLC between 1987 and 2004 at the Thoracic Surgery Units of Kobe University Graduate School of Medicine and Hyogo Cancer Center. Among the investigated patients, 46 exhibited positive cytological findings. The prognosis of these patients was significantly worse compared to that of patients without positive PLC. Of the 844 pathological stage I patients, 18 had a positive PLC status and their prognosis was significantly worse compared to that of patients with stage I disease without positive PLC. In conclusion, positive PLC findings were associated with a poor prognosis and this finding was significant for patients with stage I disease. These results suggest the need for PLC status evaluation during staging and treatment planning in patients with NSCLC.
Keywords: non-small-cell lung cancer; pleural lavage cytology; prognostic factor.