cancer staging, a system for describing the exact location, size, and extent of spread of a malignant tumor, used to plan treatment and predict prognosis. Staging may involve a physical examination, diagnostic procedures, surgical exploration, and histological examination. The system developed by the American Joint Committee for Cancer Staging and End Results Reporting uses the letter T to represent the tumor, N for the regional lymph node involvement, M for distant metastases, and numeric subscripts in each category to indicate the degree of dissemination. According to this system T1N0M0 designates a small localized tumor; T2N1M0 is a larger primary tumor that has extended to regional nodes; and T4N3M3 is a very large lesion involving regional nodes and distant sites. PTNM is a TNM confirmed by pathology. CTNM is a clinical assessment of TNM. Tx is used when the tumor is unevaluated.
