Evaluation of extratumoral lymphatic permeation in non-small cell lung cancer as a means of predicting outcome

SummaryBackgroundLymphatic permeation (ly) has been described as a potential prognostic factor for non-small cell lung cancer (NSCLC).MethodsThe purpose of this study was to analyze whether evaluation of the presence or absence of ly and its location (ly 0: absent, N = 464; ly 1: intratumoral, N = 42; ly 2: extratumoral, N = 52) provides an appropriate means of predicting the outcome of NSCLC. We investigated the clinical implications of ly in 558 consecutive patients with surgically resected NSCLC.ResultsEvaluation according to ly status showed that the recurrence-free survival (RFS) time of the ly 2 patients was significantly shorter than that of the ly 0 patients (P < 0.0001), the ly 1 patients (P = 0.0028). A significant difference in RFS time was also observed between the ly 0 patients and the ly 1 patients (P = 0.0025). RFS time of the ly 0 patients was significantly longer than that of the ly 1 plus ly 2 patients (P < 0.0001). We also evaluated the patients with pathological stage I disease (N = 378) separately. The RFS time of the ly 2 patients (N = 9) was significantly shorter than that of the ly 0 plus ly 1 patients (P < 0.0001). In the nine ly 2 patients, six developed a distant metastasis within 1 year. A multivariate analysis revealed that ly status (ly 0 plus ly 1 versus ly 2) was an independent prognostic factor (P = 0.0116), demonstrating the significant prognostic value of extratumoral lymphatic permeation in NSCLC.ConclusionsThese results indicate that ly status is a good prognostic marker of poorer outcome in patients with resected NSCLC.