P1.08-002 The Prognostic Significance of Pleural Lavage Cytology before and after Lung Resection

Abstract

The status of intraoperative pleural lavage cytology (PLC) has been reported to be a predictive factor of recurrence in resected non-small cell lung cancer (NSCLC). However, prognostic significance of PLC remains unclear and it has not been included in the TNM classification. Furthermore, the appropriate timing to perform PLC, before lung resection (pre-PLC) or after lung resection (post-PLC), is not evident. Of 627 consecutive patients with NSCLC who underwent complete resection (segmentectomy or more) in Tottori University Hospital from January 2004 to December 2013, 615 patients who were performed both pre-PLC and post-PLC were enrolled in present study. Patients were divided into four groups, negative pre-PLC / negative post-PLC (Group A), positive pre-PLC / negative post-PLC (Group B), negative pre-PLC / positive post-PLC (Group C), and positive pre-PLC / positive post-PLC (Group D). Then differences in recurrence free survival (RFS) and disease specific survival (DSS) among each groups were analyzed by log-rank test. Moreover, PLC status as a prognostic factor for RFS and DSS were analyzed using univariate and multivariate Cox regression models. There were 573 patients in Group A, 11 in Group B, 14 in Group C, and 17 in Group D, respectively. Survival analysis revealed significant differences in not only RFS but also DSS between Group A and Group B (log-rank test, p<0.001), Group A and Group C (p<0.001), Group A and Group D (p<0.001), respectively. However, there was no significant differences among Group B, C, and D (p=0.861). Multivariate analysis identified advanced age (75≤), male sex, larger tumor size (3cm<), lymph node metastasis, lymphatic invasion, and positive PLC status (Hazard Ratio: 3.735, 95% confidence interval: 2.312 to 6.063, p<0.001) as statistically independent prognostic factors for DSS. In conclusion, positivity of both pre-PLC and post-PLC were significant worse prognostic factor for DSS of patients with completely resected NSCLC. Therefore, surgeons should consider performing PLC both before and after lung resection to estimate patients’ prognosis correctly. Moreover, further accumulation of knowledge about PLC is needed to reflect PLC status in the TNM classification.