Purpose: The TNM staging remains the best prognostic descriptor of lung cancer; however, new independent prognostic factors are needed, particularly for early stage disease.
Methods: An evaluation of the pleural lavage cytology (PLC) was performed in 436 consecutive NSCLC patients who underwent surgical resection; clinical, pathological and follow-up data were available for 414 patients.
Results: The PLC was positive in 15 patients (3.6 %). The overall five-year survival was 35.9 % in PLC-positive and 57.8 % in PLC-negative patients (p = 0.004). To compare groups with the same prognostic characteristics, the analysis was restricted to p-stage I patients, but the survival remained worse in the PLC-positive patients (42.9 vs 69.4 %; p = 0.001). Recurrence was also observed more frequently in PLC-positive cases: 69.2 vs 34.5 %, OR 4.28 (95 % CI 1.29-14.18; p = 0.01). Among the PLC-positive patients, no difference between the local (44.4 %) and distant (55.6 %) relapse patterns was found (p = 0.82). The multivariate analysis identified four independent prognostic factors: age (p < 0.001), disease stage (p < 0.001), gender (p = 0.025) and PLC status (p = 0.012).
Conclusions: PLC is an independent prognostic factor for NSCLC. PLC-positive NSCLC patients have a worse overall survival and a higher recurrence rate, even in stage I disease. PLC-positive patients should be considered a high risk category, who should potentially be eligible for adjuvant therapy regardless of their p-stage.