Impact of Pleural Lavage Cytology Positivity on Early Recurrence After Surgery for Non-Small Cell Lung Cancer.

ABSTRACT

OBJECTIVE: The aim of this study was to elucidate the impact of pleural lavage cytology positivity on early recurrence in patients operated on non-small cell lung cancer (NSCLC). METHODS: This is a multicentre prospective cohort study of 684 patients undergoing an anatomical lung resection for NSCLC between October 2015 and October 2017 at 12 national centres. A pleural lavage was performed before and after lung resection. The association between the different predictors of early recurrence and PLC positivity was performed using univariate and multivariate logistic regression models. A propensity score analysis was performed by inverse probability weighting (IPSW) using average treatment effect (ATE) estimation to analyse the impact of PLC positivity on early recurrence. RESULTS: Overall PLC positivity was observed in 15 patients (2.2%). After two years, 193 patients (28.2%) relapsed, 182 (27.2%) with a negative PLC and 11 (73.3%) with a positive PLC (p<0.001). Factors associated to early recurrence were adenocarcinoma histology (OR=1.59, 95%CI 1.06-2.38, p=0.025), visceral pleural invasion (OR=1.59, 95%CI 1.04-2.4, p=0.03), lymph node involvement (OR=1.84, 95%CI 1.14-2.96, p=0.013), advanced pathological stage (OR=2.12, 95%CI 1.27-3.54, p=0.004) and PLC positivity (OR=4.14, 95%CI 1.25-16.36, p=0.028). After IPSW, PLC positivity was associated with an increased risk of early recurrence (OR=3.46, 95%CI 2.25-5.36, p<0.001). CONCLUSIONS: Positive pleural lavage cytology was found to be the strongest predictor of early recurrence.