Table 6.
Definition of M category for the American Joint Committee on Cancer (AJCC) TNM staging.
| M Category | M Criteria |
|
|---|---|---|
| Anatomic Site | LDH Level | |
|
| ||
| M0 | No evidence of distant metastasis | Not applicable |
|
| ||
| M1 | Evidence of distant metastasis | See below |
|
| ||
| M1a | Distant metastasis to skin, soft tissue including muscle, and/or nonregional lymph node | Not recorded or unspecified |
| M1a(0) | Not elevated | |
| M1a(1) | Elevated | |
|
| ||
| M1b | Distant metastasis to lung with or without M1a sites of disease | Not recorded or unspecified |
| M1b(0) | Not elevated | |
| M1b(1) | Elevated | |
|
| ||
| M1c | Distant metastasis to non-CNS visceral sites with or without M1a or M1b sites of disease | Not recorded or unspecified |
| M1c(0) | Not elevated | |
| M1c(1) | Elevated | |
|
| ||
| M1d | Distant metastasis to CNS with or without M1a or M1c sites of disease | Not recorded or unspecified |
| M1d(0) | Not elevated | |
| M1d(1) | Elevated | |
With permission from Gershenwald JE, Scolyer RA, Hess KR, et al. Melanoma of the skin. In: Amin MB, Edge SB, Greene FL, et al, eds. AJCC Cancer Staging Manual 8th ed. Springer International Publishing; 2017:563–585.
LDH, lactate dehydrogenase; CNS, central nervous system.