The Intraductal Carcinoma Component Is a Significant Prognostic Parameter in Patients with Invasive Ductal Carcinoma of the Pancreas

We have sometimes encountered invasive ductal carcinomas (IDCs) of the pancreas containing intraductal carcinoma components in the intra‐ and/or extra‐tumor area. The purpose of this study was to investigate whether intraductal carcinoma components would be useful for predicting the outcome of IDC patients. Forty‐seven surgically treated IDCs were examined, and all histological tumor sections were stained with Elastica to accurately confirm intraductal carcinoma components. Well‐known clinicopathological parameters that exhibited a significant correlation in the univariate analyses for predicting disease‐free survival (DFS) and overall survival (OS) were entered into the Cox proportional hazard multivariate analysis. Since the lowest P‐value predicting DFS or OS periods was observed in IDCs with more than 10% intraductal carcinoma components and those with 10% or less intraductal carcinoma components (P=0.028 and P=0.019), we established the cutoff value of intraductal carcinoma components at 10%. In the multivariate analyses for DFS and OS, the presence of more than 10% intraductal carcinoma components showed a marginally significant increase in the hazard rate (HR) of tumor recurrence (P=0.067) and significantly increased the HR of mortality (P=0.040). The present study demonstrated that IDCs with more than 10% intraductal carcinoma components were associated with a significantly better patient outcome than those with 10% or less intraductal carcinoma components.