Vascular invasion in pancreatic cancer: Tumor biology or tumor topography?

Abstract

Although vascular resection in pancreatic adenocarcinoma increases the resection rate, involvement of the vascular structures frequently is assumed to be associated with a more aggressive tumor biology and tumor cell dissemination. Our study's aim was to assess the correlation of vascular tumor involvement with adverse, clinicopathologic prognosticators and with the extent of tumor cell dissemination. We studied 108 patients who had undergone pancreatic resection, of whom 39 underwent vascular resection. Clinical parameters and the postoperative course were recorded. Formalin-embedded lymph node samples as well as bone marrow aspirates were screened immunohistochemically for disseminated tumor cells. Univariate and multivariate analyses were performed using the log-rank test and the Cox proportional-hazard models. Overall, 2,388 lymph nodes and bone marrow aspirates from 49 matched patients were screened immunohistochemically. Fully 50% of the patients had disseminated tumor cells in lymph nodes and 27% in bone marrow. The mean observation period in cohort was 28 months. Vascular resection did not correlate with prognostically relevant parameters. Disseminated tumor cells in lymph nodes were associated with a decrease in relapse-free survival (P = .016) and were confirmed as independent indicators for a decrease in metastasis-free survival at multivariate analysis. There was no adverse prognostic influence of vascular resection, and there was no increased frequency of disseminated tumor cells in patients undergoing vascular resection. These results support the hypothesis that the presence of vascular tumor involvement of peripancreatic vessels seems to be an indicator of unfavorable tumor topography, instead of being a sign of adverse tumor biology. Thus, vascular resection in pancreatic cancer appears to be warranted to achieve tumor-free margins.