Validation of a Proposed Tumor Regression Grading Scheme for Pancreatic Ductal Adenocarcinoma After Neoadjuvant Therapy as a Prognostic Indicator for Survival

Neoadjuvant therapy has been increasingly used to treat patients with potentially resectable pancreatic ductal adenocarcinoma (PDAC). Although the College of American Pathologists (CAP) grading scheme for tumor response in posttherapy specimens has been used, its clinical significance has not been validated. Previously, we proposed a 3-tier histologic tumor regression grading (HTRG) scheme (HTRG 0, no viable tumor; HTRG 1, <5% viable tumor...