Abstract: This article combines the research data of the proposed version officially released by the AJCC Colon Cancer Expert Panel and relevant literature to interpret the key updates of the proposed AJCC 9th Edition TNM staging system for colon cancer,analyzing its update methods,main changes,and their impacts on clinical and pathological practices.It should be particularly noted that the current version is only a proposed scheme put forward by the expert panel and has not been officially approved and released by the AJCC.The proposed staging system is based on largescale realworld data from the National Cancer Database (NCDB) in the United States,using recursive partitioning and regression tree analysis to make structural adjustments for the nonhierarchical survival outcomes existing in the 8th edition.The main updates include:moderately increasing the weight of T stage in prognostic stratification;listing tumor deposits (TDs) as an independent prognostic variable;scientifically adjusting N staging so that it can more reasonably reflect prognostic value in coordination with T stage and TDs.The new proposed staging framework has more biological significance and clearer prognostic hierarchy,and also puts forward higher requirements for the accuracy of pathological reports and clinical individualized treatment.The proposed AJCC 9th Edition TNM staging system for colon cancer is based on realworld prognostic data and is expected to solve the nonhierarchical problem existing in previous staging systems,marking that colon cancer staging is expected to evolve from a mainly anatomybased model to a new stage that integrates tumor biological behavior.

Key words: colon cancer;TNM staging;AJCC 9th edition;tumor deposit;prognostic stratification