The most widely used system for cancer staging in the world. Created by the American Joint Committee on Cancer (AJCC), the TNM system defines cancer by features of the primary tumor, the presence or absence of tumor spread to nearby lymph nodes, and the presence or absence of metastasis to distant sites.

Classification based on T (tumor invasion), N (lymph node involvement), and M (presence or absence of metastatic spread). Various TNM combinations are colected onto staging groups based on similar clinical performance.

Classification of tumors based on size and extent of the tumors (T), the affected or non-affected lymph nodes (N), or other organs (M, metastasis).