Circumferential resection margin (CRM) in pancreatic cancer

Abstract

Abstract Many studies have shown improved survival in patients with negative resection margin status after surgical resection for pancreatic ductal adenocarcinoma (PDAC). The resection margin most often affected by incomplete resection is the circumferential resection margin (CRM), a fact that can at least partially be attributed to the discontinuous tumor growth of PDAC and its abundant stromal reaction. The CRM consists of the anterior and posterior, and, in case of pancreatic head resections, medial pancreatic surface. However, contradictory definitions, inconsistent nomenclature and non-standardized processing of the CRM are hampering not only adequate routine diagnostics, but also the generation of reliable data in research contexts. An inadequate pathological evaluation of pancreatic resection specimens results in a severe underestimation of incomplete resections. While standardization of CRM assessment and of margin clearance evaluation are an urgent goal for the near future, pathology laboratories should already aim at meticulous work-up and reporting of pancreatic resection specimens. This can include additional information, such as the exact localization of the closest margin, the exact measurement of the distance of the tumor to the closest margin, and the description of the type of tumor cell formations closest to the margin (i.e. primary tumor vs. perineural or vascular invasion).