Enhanced primary tumor delineation in pancreatic adenocarcinoma using ultrasmall super paramagnetic iron oxide nanoparticle-ferumoxytol: an initial experience with histopathologic correlation

Abstract

Sandeep S Hedgire,1 Mari Mino-Kenudson,2 Azadeh Elmi,1 Sarah Thayer,3 Carlos Fernandez-del Castillo,3 Mukesh G Harisinghani11Department of Abdominal Imaging and Intervention, 2Department of Pathology, 3Department of Surgery, Massachusetts General Hospital, Boston, MA, USAPurpose: To evaluate the role of ferumoxytol-enhanced magnetic resonance imaging (MRI) in delineating primary pancreatic tumors in patients undergoing preoperative neoadjuvant therapy.Materials and methods: Eight patients with pancreatic adenocarcinoma were enrolled in this study, and underwent MRI scans at baseline, immediate post, and at the 48 hour time point after ferumoxytol injection with quantitative T2* sequences. The patients were categorized into two groups; group A received preoperative neoadjuvant therapy and group B did not. The T2* of the primary pancreatic tumor and adjacent parenchyma was recorded at baseline and the 48 hour time point. After surgery, the primary tumors were assessed histopathologically for fibrosis and inflammation.Results: The mean T2* of the primary tumor and adjacent parenchyma at 48 hours in group A were 22.11 ms and 16.34 ms, respectively; in group B, these values were 23.96 ms and 23.26 ms, respectively. The T2* difference between the tumor and adjacent parenchyma in group A was more pronounced compared to in group B. The tumor margins were subjectively more distinct in group A compared to group B. Histopathologic evaluation showed a rim of dense fibrosis with atrophic acini at the periphery of the lesion in group A. Conversely, intact tumor cells/glands were present at the periphery of the tumor in group B.Conclusion: Ferumoxytol-enhanced MRI scans in patients receiving preoperative neoadjuvant therapy may offer enhanced primary tumor delineation, contributing towards achieving disease-free margin at the time of surgery, and thus improving the prognosis of pancreatic carcinomas.Keywords: pancreatic cancer, tumor margin, neoadjuvant therapy, borderline resectable pancreatic cancer