Table 1.
TNM classification descriptors and additional modifiers
| Descriptor | Values | Meaning |
|---|---|---|
| T | 0-4, is, X | Extent of the primary tumour |
| N | 0-3, X | Extent of metastasis in regional lymph nodes |
| M | 0-1 | Existence of distant metastasis |
| Prefix to T, N, M | p, c | Clinical (pre-therapeutical) or pathological (post-surgical assessment) |
| Suffix to pNn | (mi) | Micrometastasis (< 0.2 cm) |
| Suffix to pNn | (sn) | Sentinel lymph node metastasis |
| Suffix to pN0 or pM0 | (i+), (mol+) | Isolated tumour cells, positive findings |
| G | X, 1-4 | Histopathological grading |
| Suffix to T | (m) | Multiple primary tumours at a single side |
| Prefix to c/ p | y | Assessment during multimodal therapy |
| Prefix to c/ p | r | Recurrent tumour |
| Prefix to c/ p | a | Assessment during autopsy |
| L | X, 0-1 | Lymphatic invasion |
| V | X, 0-2 | Venous invasion |
| Pn | X, 0-1 | Perineural invasion |
| C | 1-5 | Validity of the assessment, can follow each of T, N, M |
| R | X, 0-2 | Residual tumour |
Depending on the organ of the primary tumour, T, N, and M values can be further subdivided into levels a-c, e.g. N1a-c, N2a-c, and M1a-b in colorectal tumours