Intraductal Spread of Pancreatic Cancer

Abstract

Background: Invasive ductal adenocarcinoma of the pancreas (IDAP) also spreads through the pancreatic ductal tree. The aim of this study was to clarify the clinicopathologic features of IDAP with intraductal spread. Methods: We studied the intraductal spread of IDAP and its correlation with clinicopathologic parameters in a surgical series of 54 patients. The pancreatic ducts were analyzed by confirmation of mural elastic fibers with elastica van Gieson stain. Results: Intraductal spread of carcinoma was identified in 37 patients (69%). Such spread was frequent in well-differentiated IDAP (93%), and the number of intraductal carcinoma foci was correlated with the grade of tumor differentiation (p < 0.001). The large branch ducts were the main route of intraductal spread (64.1%). The proliferation index, evaluated using Ki67, was lower in the intraductal carcinoma components than in the associated infiltrating carcinoma components (p < 0.001). The presence or absence of intraductal spread was not correlated with age, sex, tumor location, tumor size, or stage. IDAP with intraductal spread showed a tendency, although it was not significant (p = 0.092), to be associated with longer survival compared with IDAP without intraductal spread. Conclusion: IDAP, especially of the well-differentiated type, has a tendency to spread intraductally. The difference between the Ki67 labeling indexes in the intraductal and associated infiltrating carcinoma components suggests that these components show different biological behaviors.