Prognostic impact of intratumoral vessel invasion in completely resected pathologic stage I non-small cell lung cancer

Objective: Intratumoral vessel invasion of non-small cell lung cancer is a readily available tumor-related factor that provides direct evidence of microscopic tumor invasion. We assessed the prognostic influence of intratumoral vessel invasion and its ability to provide a differential prediction of prognosis for completely resected pathologic stage I non-small cell lung cancer. Methods: We analyzed 258 patients with non-small cell lung cancer who underwent complete resection between January of 1996 and December of 2005 and were diagnosed with pathologic stage I disease. In addition to the conventional staging factors, intratumoral vessel invasion in the primary lesion was histologically evaluated by both hematoxylin-eosin and elastic staining. We examined the significance of intratumoral vessel invasion in prognosis and compared the outcomes between patients with and without this factor with stage IA and IB disease, respectively. Results: Intratumoral vessel invasion was found in 124 patients (48%). Five-year survival of patients with or without intratumoral vessel invasion was 74% and 93%, respectively. On multivariate analysis, intratumoral vessel invasion and pleural invasion were shown to be independent prognostic factors. Subgroup analyses suggested that patients with pathologic-stage IA with intratumoral vessel invasion and patients with pathologic-stage IB with both intratumoral vessel and pleural invasion had significantly worse prognosis than patients with the same pathologic stage without these factors. Conclusion: The current study indicated that intratumoral vessel invasion and pleural invasion are independent prognostic factors. Intratumoral vessel invasion status can complement the size-dependent TNM staging system in pathologic stage I non -small cell lung cancer.