A system developed by the American Joint Committee on Cancer (AJCC) that uses TNM to describe the extent of cancer in a patient’s body. T describes the size of the tumor and whether it has invaded nearby tissue. N describes whether cancer has spread to nearby lymph nodes, and M describes whether cancer has metastasized (spread to distant parts of the body). The AJCC staging system is used to describe most types of cancer. Also called TNM staging system.