T4N2M0 is the TNM staging system for malignant tumors, which is currently the most important international cancer staging system, in which the letter T refers to the size of the longest diameter of the tumor, followed by the number representing the grading of the longest diameter of the tumor, generally divided into 1-4 grades, representing the longest diameter of tumor masses of different degrees, the larger the longest diameter of the tumor masses, the larger the number. The letter N represents the number of lymph node metastasis, the same as T. The number after N is also the grading of the number of lymph node metastasis, generally divided into 1-3 grades, the more lymph nodes are metastasized, the larger the value will be.