The Impact of Pleural Lavage Cytology Both before and after Lung Resection on Recurrence of Non-Small Cell Lung Cancer

Background Pleural lavage cytology (PLC) involves cytologic examination during surgery for non-small cell lung cancer (NSCLC). The timing regarding the performance of PLC is potentially important; however, a consensus remains to be established. We sought to retrospectively analyze the impact of PLC both before (pre-PLC) and after (post-PLC) lung resection on recurrence in NSCLC. Methods From July 1994 to December 2011, 700 consecutive patients with surgically resected NSCLC were selected. Both pre-PLC and post-PLC status was tested using univariate and multivariate Cox regression analyses of recurrence-free survival (RFS). Results By analyzing RFS, post-PLC status but not pre-PLC status together with pathologic N factor and pathologic stage, was identified as an independent factor for poor prognosis (p = 0.0040). A statistically significant association was observed between positive post-PLC status and pleural invasion, pathologic T factor, pathologic N factor, pathologic stage, and postoperative recurrence (p = 0.0004, p = 0.0033, p = 0.0001, p < 0.0001, and p < 0.0001, respectively). The RFS was similarly worse for patients with positive post-PLC status regardless of pre-PLC status. Conversely, the RFS was similarly better for patients with negative post-PLC status regardless of pre-PLC status. Conclusions Positive post-PLC status was found to be a predictive factor for postoperative recurrence in patients with surgically resected NSCLC. Moreover, post-PLC status might be an additional factor not only for identifying a patient group with a high risk of postoperative recurrence, but also to avoid unnecessary treatment of patients with low risk of postoperative recurrence.