The significance and factors leading to heteroploidy in pleural lavage cytology

Introduction: Positive intraoperative pleural lavage cytology (pre-resection PLC) is considered a prognostic risk factor of primary lung cancer surgery. Positive findings suggest subclinical metastasis of malignant cells in the thoracic cavity. In this study, we attempted to determine the incidence of and risk factors for positive pleural lavage cytology (PLC) in primary lung cancer patients. Methods: We included 62 surgically treated patients who had been diagnosed with non-small-cell lung cancer and had their PLC status examined between November 2019 and November 2021. PLC was measured by the circulating tumour cell (CTC) method, and we searched for factors predictive of a PLC-positive status. Results: PLC (+) was identified in 22 of the 62 patients (35.5%) and was associated with air bronchogram (p=0.042), pathological classification (p=0.008) and tumour stage (p=0.017). There was no significant difference in other factors between PLC (+) and PLC (-) patients. Binary logistic regression analysis showed that the odds ratio of PLC positivity in the population with bronchial signs was 4.200 compared with the population without bronchial signs. Conclusion: Lung cancer patients with bronchial signs on imaging have a greater probability of PLC positivity. The probability of PLC positivity in patients with carcinoma in situ is reduced, and the probability of PLC positivity increases when the tumour metastasizes.