Lymphatic vessel invasion is a significant prognostic indicator in stage IA lung adenocarcinoma.

Background: A radical resection is considered to be the most effective treatment for resectable non-small cell lung cancer. However, even when resected in early stages (T1aN0, T1bN0) up to 20% of patients will experience recurrence. The aim of this retrospective study was to evaluate the prognostic influence of lymphatic vessel invasion (LVI) in stage IA adenocarcinoma patients.

Methods: From January 1983 to June 2003, a total of 229 consecutive patients with pT1a or T1b N0 M0 lung adenocarcinoma who had undergone radical resection and lymph node dissection were retrospectively reviewed. Sections stained by the hematoxylin-eosin and the Elastica van Gieson method were examined for the presence of LVI. The overall survival was estimated using the Kaplan-Meier method, log-rank test, and the Cox proportional hazards analysis.

Results: The median follow-up was 81 months. A total of 143 patients (62%) were able to be diagnosed with regard to the presence of LVI, while information was not provided for 86 patients (38%), who were therefore excluded from the study. LVI was noted in 22 of the evaluable patients (15%) and was not seen in the other 121 patients (85%). The 5-year overall survival rate of the LVI-negative group and the LVI-positive group was 94.5 and 70.9%, respectively (P = .003). A multivariate analysis revealed LVI to be an independent predictive factor (hazard ratio: 0.202; P = .001).

Conclusion: LVI is an independent poor prognostic factor in patients with pathologic stage IA adenocarcinoma. The T1a and T1b patients with LVI both might benefit from adjuvant chemotherapy.