Table 4.
Definition of N according to AJCC 8th edition [1].
| Category | Number of Tumor-Involved Regional Lymph Node | Presence of In-transit, Satellite, and/or Microsatellite Metastases |
|---|---|---|
| NX: Patients in whom the regional nodes cannot be assessed | N/A | No |
| N0: No regional metastases detected | N/A | No |
| N1 | 1 tumor-involved node or in-transit, satellite, and/or microsatellite metastases with no tumor-involved node | |
| N1a | 1 clinically occult (ie, detected by SLN biopsy) | No |
| N1b | 1 clinically detected | No |
| N1c | No regional lymph node disease | Yes |
| N2 | 2 or 3 tumor-involved nodes or in-transit, satellite, and/or microsatellite metastases with 1 tumor-involved node | |
| N2a | 2 or 3 clinically occult (ie, detected by SLN biopsy) | No |
| N2b | 2 or 3, at least 1 of which was clinically detected | No |
| N2c | 1 clinically occult or clinically detected | Yes |
| N3 | 4 or more tumor-involved nodes or in-transit, satellite, and/or microsatellite metastases with 2 or more tumor-involved nodes, or any number of matted nodes without or with in-transit, satellite, and/or microsatellite metastases | |
| N3a | 4 or more clinically occult (ie, detected by SLN biopsy) | No |
| N3b | 4 or more, at least one of which was clinically detected, or presence of any number of matted nodes | No |
| N3c | 2 or more clinically occult or clinically detected and/or presence of any number of matted nodes | Yes |