Table 3. Distant Metastasis (M)a
| M0 | No detectable evidence of distant metastases. |
| M1a | Metastases to skin, subcutaneous, or distant lymph nodes. |
| M1b | Metastases to lung. |
| M1c | Metastases to all other visceral sites or distant metastases to any site combined with an elevated serum LDH. |
| Note: Serum LDH is incorporated into the M category as shown below: |
| M Classification | Site | Serum LDH |
| M1a | Distant skin, subcutaneous, or nodal mets. | Normal. |
| M1b | Lung metastases. | Normal. |
| M1c | All other visceral metastases. | Normal. |
| Any distant metastasis. | Elevated. |
| LDH = lactate dehydrogenase. |
| aReprinted with permission from AJCC: Melanoma of the skin. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 325-44. |
