The impact on survival of positive intraoperative pleural lavage cytology in patients with non–small-cell lung cancer

Objective The aim of this study was to analyze intraoperative pleural lavage cytology results in patients with non–small-cell lung cancer and quantify the impact on survival and recurrence. Methods From August 1992 through November 2006, pleural lavage cytology results before and after lung resection were both available in 2178 patients with non–small-cell lung cancer. We assessed the pre–pleural lavage cytology impact on survival, comparing with 9 factors available before lung resection by multivariate analyses. We also compared the impact with that of pleural dissemination or malignant pleural effusion. For post–pleural lavage cytology, we analyzed its survival impact in relation with 15 clinicopathologic factors, including those available after resection, by multivariate analyses. Results Pre–pleural lavage cytology proved to be a strong independent prognostic factor, but the 5-year survival rate was 37% in 65 patients without dissemination but with a positive pre–pleural lavage cytology, which was significantly higher than 12% in 86 patients with dissemination. When factors available after resection were combined, post–pleural lavage cytology showed a stronger survival impact than pre–pleural lavage cytology. Post–pleural lavage cytology was also a strong predictor of recurrence. The positive post–pleural lavage cytology group had a marginally, but not significantly, better survival compared with the malignant pleural effusion group. Almost all patients with positive post–pleural lavage cytology relapsed within 5 years. Conclusions Pre–pleural lavage cytology is of less use in clinical practice. Post–pleural lavage cytology was a very strong independent prognostic factor, and almost all patients with positive post–pleural lavage cytology relapsed within 5 years. We propose that positive post–pleural lavage cytology disease should be classified to pathologic T4 and managed similarly to dissemination.