Clinical significance of pleural lavage cytology in non-small cell lung cancer: A meta-analysis

Abstract

18031 Background: The clinical significance of pleural lavage cytology (PLC) in non-small-cell lung cancer (NSCLC) remains controversial. This study was performed to estimate the associations of positive PLC with the main clinicopathological characteristics, and its prognostic value. Methods: PLC studies were identified on Medline, supplemented by manual search of bibliographies and proceedings. Authors were contacted for updated information. The quality of the studies was evaluated, and the data were extracted. Pooled odds ratios (ORs) and pooled hazard ratios (HRs) with confidence intervals [95% CIs] were calculated to evaluate the association of positive PLC with clinico-pathological characteristics and survival respectively. Results: Nineteen articles assessing PLC in NSCLC were selected for this study after exclusion of repeated publications or reports with little clinical detail. Positive PLC was diagnosed in 10.2% (516) of a total of 5073 patients. Positive PLC was strongly associated with lymphatic permeation (OR 4.96 [3.29, 7.54]), pleural invasion (OR 4.38 [2.16, 8.89], and vascular involvement (OR 2.94 [1.99, 4.35]). It was also found to be associated with advanced T stage, N stage, and TNM stage. Positive PLC was more frequent in adenocarcinoma than in squamous cell carcinoma (OR 2.32, [1.51, 3.52]). It was relatively more common in moderately- and poorly-differentiated tumors than in well-differentiated tumors (OR 1.89 [0.86, 4.16]). No association was found between positive PLC and fine needle aspiration cytology (OR 1.04 [0.58, 1.81]). Positive PLC was associated with high overall recurrence (OR 2.51 [1.79, 3.53]), as well as high local recurrence (OR 3.85 [1.57, 9.44]) and distant recurrence (2.58 [1.76, 3.76]). In analysis of survival, the overall HR for mortality was 2.43 [1.87, 3.16], suggesting significantly poorer survival for patients with positive PLC. Conclusions: Positive PLC in NSCLC is strongly associated with several existing poor prognosticators including pleural invasion, lymphatic spread, and vascular involvement. It may indicate locally advanced disease with high risk of recurrence and poor survival. We recommend that the PLC test be included in future clinical trials of adjuvant therapy for patients with NSCLC. No significant financial relationships to disclose.