Table 1
TNM classification for breast cancer
| T (tumor size) | |
| TX | Primary tumor cannot be assessed |
| T0 | No evidence of primary tumor |
| Tis | Carcinoma in situ; intraductal carcinoma, lobular carcinoma in situ, or Paget's disease of the nipple with no associated tumor |
| T1 | Tumor 2.0 cm or less in greatest dimension |
| T1mic: microinvasion 0.1 cm or less in greatest dimension | |
| T1a: tumor more than 0.1 cm but not more than 0.5 cm in greatest dimension | |
| T1b: tumor more than 0.5 cm but not more than 1.0 cm in greatest dimension | |
| T1c: tumor more than 1.0 cm but not more than 2.0 cm in greatest dimension | |
| T2 | Tumor more than 2.0 cm but not more than 5.0 cm in greatest dimension |
| T3 | Tumor more than 5.0 cm in greatest dimension |
| T4 | Tumor of any size with direct extension to |
| T4a: extension to chest wall | |
| T4b: edema (including peau d'orange) or ulceration of the skin of the breast or satellite skin nodules confined to the same breast | |
| T4c: both of the above (T4a and T4b) | |
| T4d: inflammatory carcinoma | |
| N (nodes) | |
| NX | Regional lymph nodes cannot be assessed (e.g. previously removed) |
| N0 | No regional lymph node metastasis |
| N1 | Metastasis to movable ipsilateral axillary lymph node(s) |
| pN1a: only micrometastasis (none larger than 0.2 cm) | |
| pN1b: metastasis to lymph node(s), any larger than 0.2 cm | |
| pN1bi: metastasis to one to three lymph nodes, any more than 0.2 cm and all <2.0 cm in greatest dimension | |
| pN1bii: metastasis to four or more lymph nodes, any more than 0.2 cm and all <2.0 cm in greatest dimension | |
| pN1biii: extension of tumor beyond the capsule of a lymph node metastasis <2.0 cm in greatest dimension | |
| pN1biv: metastasis to a lymph node 2.0 cm or more in greatest dimension | |
| N2 | Metastasis to ipsilateral axillary lymph node(s) fixed to each other or to other structures |
| N3 | Metastasis to ipsilateral internal mammary lymph node(s) |
| M (distant metastasis) | |
| MX | Presence of distant metastasis cannot be assessed |
| M0 | No distant metastasis |
| M1 | Distant metastasis present (includes metastasis to ipsilateral supraclavicular lymph nodes) |
-
p, pathologically determined.
