Clinical value of pleural lavage cytological positivity in lung cancer patients without intraoperative malignant pleuritis. Recurrent pattern based on semiquantitative analysis of tumor cells in pleural lavage

Prognostic Value of Pleural Lavage Cytology in Patients with Lung Cancer Resection: An Updated Meta-Analysis

OBJECTIVE

Pleural lavage cytology (PLC) is considered as a possible tool for assessing prognosis of lung cancer patients. We aimed to comprehensively review the prognosis value of PLC in patients undergoing surgical resection.

METHODS

We searched 4 electronic databases for relevant studies comparing positive PLC and negative PLC. The primary outcomes included survival rate and recurrence rate at maximum follow-up.

RESULTS

The meta-analysis included 28 studies, with a total of 20,714 patients. For the overall survival rate of all stages, the results demonstrated that positive pre-resection, post-resection and pooled PLC were associated with unfavorable survival: hazard ratio (HR) 2.89 (95% confidence interval [CI] 2.48-3.37), 2.70 (1.90-3.83), and 2.89 (2.52-3.31), respectively. For the stage I survival rate, the combined results also suggested that positive pre-resection, post-resection and pooled PLC were associated with unfavorable survival: HR 3.29 (95% CI 2.55-4.25), 4.85 (2.31-10.20), and 3.16 (2.53-3.94), respectively. Furthermore, a meta-analysis of 14 studies included 14,279 patients showed that positive pre-resection, post-resection and pooled PLC were associated with an increased risk of overall recurrence: risk ratio (RR) 2.45 (95% CI 1.91-3.15), 2.37 (1.11-5.09), and 2.37 (95% CI 2.00-2.80), respectively. Positive PLC was also associated with a high pleural recurrence (RR 4.77; 95% CI 3.13-7.26) or distant recurrence (RR 2.33; 95% CI 1.65-3.29).

CONCLUSIONS

Both positive pre- resection and post-resection PLC are associated with not only higher tumor recurrence but also unfavorable survival outcomes in patients with lung cancer resection. This technique can therefore act as a strong prognostic factor for tumor recurrence and adverse survival rates.

Clinical relevance of intraoperative pleural lavage cytology in non-small cell lung cancer

BACKGROUND

Intraoperative pleural lavage cytology for patients with lung cancer has been reported to be useful in detecting subclinical pleural dissemination. However, this procedure is not necessary for the staging of lung cancer in the current TNM staging system.

METHODS

Clinical records of 1025 patients with non-small cell lung cancer who underwent surgery were retrospectively reviewed and evaluated for the clinical relevance of intraoperative pleural lavage cytology.

RESULTS

Specimens of 37 patients (3.6%) were positive for pleural lavage cytology (PLC). Patients were categorized into three groups: positive PLC group, 27 patients with positive PLC without malignant pleural effusion or pleural dissemination; pleural dissemination (PD) group, 21 patients with malignant pleural effusion or PD; negative PLC group, 977 patients with negative PLC or negative PLC without PD. The positive PLC group had a significantly higher ratio of adenocarcinomas than the negative PLC group (p = 0.014). There was a significant difference in distribution of pleural factors between the positive and negative PLC groups (p < 0.001). Survival in the positive PLC group was significantly worse than in the negative PLC group (p = 0.007), especially in pathologic stage I (p = 0.001), but significantly better than in the PD group (p = 0.038). PLC status was found to be a significant independent prognostic factor in the multivariate analysis (p = 0.016).

CONCLUSIONS

The present study demonstrates the clinical relevance of intraoperative PLC in early stage non-small cell lung cancer. The result of intraoperative PLC should be involved in the staging system of lung cancer.