Prognostic implication of lymphatic vessel invasion in stage IB (pT2aN0M0) non-small cell lung cancer

Purpose To clarify the prognostic factors for recently revised stage IB non-small cell lung cancer. Methods Twenty-six specimens of completely resected stage IB (pT2aN0M0) non-small cell lung cancer were studied. Clinicopathological profiles of the 26 patients, including age, sex, smoking status, tumor size, histology, pleural invasion, and lymphatic and blood vessel invasion, were assessed. Correlation between tumor recurrence and these factors was assessed by statistical analysis. Results Lymphatic vessel invasion was the only statistically significant factor for postoperative tumor recurrence as assessed by multivariate analysis. Kaplan-Meier survival curves showed a 5-year recurrence-free rate of 77.8% in 26 patients with no lymphatic vessel invasion compared with 28.6% in those with lymphatic vessel invasion. Conclusion Lymphatic vessel invasion of cancer cells was indicated as an independent prognostic factor in revised stage IB non-small cell lung cancer.