Since the foundation of American Joint Committee on Cancer (AJCC), AJCC maintains the staging system that is used worldwidely. AJCC published its first cancer staging manual in 1977. Until 4th edition, AJCC staging system used 3 tiers system for T stage. In October 2016, the 8th edition of the AJCC Cancer Staging Manual was published to be used starting in January 2018. Up until the 7th edition AJCC cancer staging system, the staging system for pancreatic cancer has not changed much since the 6th edition which was published in 2002.1,2 The definition of T and N categories has remained more or less the same from the 5th edition in 1997.3 However, the new 8th edition has some changes in the staging of pancreatic cancer including the definitions of the T and N categories.
For the T category classification, T1 tumors are subcategorized into T1a, T1b, and T1c based on size. In addition, the T1, T2, and T3 categories are defined solely based on the size and extrapancreatic extension of the tumor is no longer taken into consideration. For the N category, node-positive disease is now subdivided into N1 and N2 based on the number of metastasized lymph nodes (LNs).
These changes have been made based on several studies. However, there are still only a limited number of reports on its validation. Furthermore, because most of the available reports were not based on multinational studies, whether global application of the new edition is possible remains unknown. In this lecture, we will touch the clinical meaning of changed AJCC staging system and share the our experience of global validation including Asian as well as USA.