Pathological examination of CT findings of tumor infiltration to the periarterial plexus in pancreatic cancer.

Abstract

644 Background: The radiographic diagnosis of tumor infiltration into the periarterial plexus in pancreatic cancer is important because it is related to the classification, however, it is difficult to distinguish the abnormal shadow along the artery caused by inflammation or cancer infiltration. The aim of this study is to investigate CT values of the abnormal shadow along artery could distinguish between inflammation and tumor invasion. Methods: Study 1: Of 26 patients who underwent DP-CAR between 2009 and 2018, we analyzed 19 patients who had dynamic CT and obtained sagittal slice taken 120 seconds after injection with less than 2.5 mm slice thickness. At first, we measured CT values at upper and lower point of CeA and CHA each sagittal slice using CT. Next, we evaluated tumor invasion at the upper and lower plexus of CeA and CHA in each section of the pathological specimen, and evaluated the relationship between the tumor invasion and the CT value. Study 2: Using these 19 patients and 40 patients who underwent DP for PDAC between 2010 and 2014, we analyzed the relation between CT value and long-term states. Results: Study 1: CT value was totally measured at the 606 points using 19 patients who underwent DP-CAR. At the 490 points, we did not observe cancer infiltration and fibrosis. At the 70 points, we observed fibrosis without cancer cells. At the 46 points, we observed cancer infiltration. CT value was significantly higher in the tumor infiltration group than that in the without cancer infiltration and fibrosis group (P < 0.01). Study 2: The best cut-off of CT value of the presence of cancer infiltration was 44.9 HU using ROC curve (AUC = 0.861). The median survival time of patients who had the points of CT value > 44.9 HU around arteries was significantly shorter than that of patients who did not have the points of CT value > 44.9 HU (2.17 vs. 4.55 years, p = 0.03). Conclusions: The CT value around the arteries was significantly higher in the points of pathological tumor infiltration than that in the points of fibrosis without cancer cells. The best cut-off CT value of the presence of cancer infiltration around arteries was 44.9 HU, and the presence of the point of CT value > 44.9 HU around arteries was associated with poor survival.