Table 2:
Selection of N-stages for staging of breast cancer based on the 7th edition of the TNM staging criteria
| Stage | Description |
|---|---|
| N0 | Cancer has not spread to nearby lymph nodes |
| N0(i+) | Lymph nodes only contain ITCs |
| N1mi | Micro-metastases in 1 to 3 lymph nodes axillary |
| N1a | Cancer has spread to 1 to 3 lymph nodes axillary, with at least 1 macro-metastasis |
| N1b | Cancer has spread to internal mammary lymph nodes, but this spread could only be found on sentinel lymph node biopsy |
| N1c | Both N1a and N1b apply |
| N2a | Cancer has spread to 4 to 9 lymph nodes under the arm, with at least 1 macro-metastasis |
| N2b | Metastases in clinically detected internal mammary lymph nodes in the absence of axillary lymph node metastases |