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

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).

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.

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).

Positive pleural lavage cytology was found to be the strongest predictor of early recurrence.