Prognostic impact of perineural, blood and lymph vessel invasion for esophageal cancer

Background: With a median survival of ⟨22 months esophageal cancer is one of the most aggressive tumors, up to 20% of node negative patients develop systemic relapse. Studies investigating the prognostic impact of tumor-micro-invasion in blood (AI) and lymphatic vessels (LVI) as well as perineural invasion (PNI) have shown inconsistent results. The aim of the present study was to investigate the prognostic value of the aforementioned factors in a large homogenously treated cohort of patients with esophageal cancer. Methods: Data from 695 patients with surgically treated esophageal cancer were analyzed. AI, LVI and PNI were determined and data were statistically correlated with clinico-pathological parameters and survival of the patients. Results: Thirteen percent of all specimens showed an AI, 35% a LVI and 5% a PNI. The invasion factors were mostly significantly correlated with the established prognostic parameter, including bone marrow micro-metastases. Kaplan-Meier analysis revealed a prognostic impact for LVI in both cancer subtypes, while AI and PNI were significant factors in adenocarcinoma only. In multivariate analysis, none showed statistical significance. However, sub-analysis of completely resected, node negative and non-metastasized patients showed a significant prognostic impact of LVI. Conclusion: The prognostic significance of AI, LVI and PNI seems to be limited compared to the established prognostic parameters of the UICC staging system. In completely resected, node negative and non-metastasized patients, LVI is an independent prognostic parameter for a worse outcome. Those patients might benfit from additional treatment or more intensive follow up.