Positive intraoperative pleural lavage cytology is a predictive marker of disease recurrence in stage I lung adenocarcinoma.

OBJECTIVES: This study aimed at analysing the relationship between the pleural lavage cytology (PLC) status and clinicopathological characteristics, including the outcome of examined patients and tumour recurrence sites in surgically resected stage I non-small-cell lung carcinoma.

METHODS: From April 2002 to August 2012, PLC was performed immediately after thoracotomy in 428 consecutive patients undergoing pulmonary resection for lung cancer. The relationship between clinicopathological characteristics and the PLC status was retrospectively analysed.

RESULTS: The frequency of PLC-positive results was 4.4%, and larger tumour size, stage IB and pleural invasion were found more frequently in PLC-positive patients. Patients with a PLC-positive status had significantly worse disease-free survival (DFS) than those with a PLC-negative status (PLC positive versus PLC negative: hazard ratio [HR] = 2.79, 95% confidence interval [CI]: 1.4-5.57, P < 0.004; 5-year DFS: 46.6 vs 76.5%). With regard to the PLC status and histological type, adenocarcinoma was associated with a worse DFS in PLC-positive patients when compared with PLC-negative patients (5-year DFS: 38.1 vs 81.1%, P < 0.001). In multivariate analysis, PLC status remained significantly associated with DFS in patients with a PLC-positive status having an increased risk of recurrence, compared with PLC-negative patients (HR = 2.494, 95% CI: 1.241-5.011, P = 0.01) only in the case of adenocarcinoma.

CONCLUSIONS: Our current study showed the clinicopathological characteristics associated with PLC status and demonstrated that PLC status was an independent predictor of increased recurrence in stage I lung adenocarcinoma.