Regarding TNM staging system in oncology, all of the following statements are TRUE EXCEPT:

Explanation

## TNM Staging System Overview **Key Point:** TNM is the most widely used staging system for solid tumors, but it is NOT universally applicable without modification. ### T (Tumor) Stage - Describes size and extent of primary tumor - Ranges from T0 (no evidence) to T4 (extensive local invasion) - **Correct statement** ### N (Node) Stage - Indicates number, size, and location of involved regional lymph nodes - Ranges from N0 (no nodes) to N3 (extensive nodal involvement) - Presence of any nodal involvement (N1+) typically indicates at least Stage II or higher - **Correct statement** ### M (Metastasis) Stage - M0 = no distant metastases - M1 = distant metastases present - **Correct statement** ### Why TNM is NOT universally applicable without modification - **Hematologic malignancies** (lymphomas, leukemias): Use Ann Arbor staging, not TNM - **CNS tumors**: Use WHO grading and specialized staging (e.g., Karnofsky score) - **Testicular cancer**: Uses IGCCCG classification - **Ovarian cancer**: Modified TNM with special considerations - **Breast cancer**: TNM modified with hormone receptor and HER2 status integration - **Melanoma**: Uses Breslow thickness and Clark level in addition to TNM **Clinical Pearl:** TNM is primarily for carcinomas; other tumor types require specialized staging systems. ### Stage Grouping (General) | Stage | Typical Characteristics | |-------|------------------------| | Stage I | T1-2, N0, M0 (early, localized) | | Stage II | T3 or N1, M0 (locally advanced) | | Stage III | T4 or N2-3, M0 (advanced local/regional) | | Stage IV | Any T, Any N, M1 (metastatic) |