Currently, there are no internationally accepted consensus guidelines for pathologic evaluation of posttherapy
pancreatectomy specimens. The
Neoadjuvant Therapy Working Group of Pancreatobiliary Pathology Society was formed in 2018 to review grossing protocols, literature, and major issues and to develop recommendations for pathologic evaluation of posttherapy
pancreatectomy specimens. The working group generated the following recommendations: (1) Systematic and standardized grossing and sampling protocols should be adopted for
pancreatectomy specimens for treated pancreatic ductal
adenocarcinoma (PDAC). (2) Consecutive mapping sections along the largest gross
tumor dimension are recommended to validate
tumor size by histology as required by the College of American Pathologists (CAP)
cancer protocol. (3)
Tumor size of treated PDACs should be measured microscopically as the largest dimension of
tumor outer limits that is bound by viable
tumor cells, including intervening stroma. (4) The MD Anderson grading system for
tumor response has a better correlation with prognosis and better interobserver concordance among pathologists than does the CAP system. (5) A case should not be classified as a complete response unless the entire pancreas, peripancreatic tissues, ampulla of Vater, common bile duct, and duodenum adjacent to the pancreas are submitted for microscopic examination. (6) Future studies on
tumor response of
lymph node metastases, molecular and/or immunohistochemical markers, as well as application of artificial intelligence in grading
tumor response of treated PDAC are needed. In summary, systematic, standardized pathologic evaluation, accurate
tumor size measurement, and reproducible
tumor response grading to
neoadjuvant therapy are needed for optimal patient care. The criteria and discussions provided here may provide guidance towards these goals.