Tumor (describes the primary tumor)

• TX: Primary tumor cannot be assessed.
• T0: No evidence of primary tumor
• Tis: Melanoma that invades only the outer layer of skin (melanoma in situ)
• T1: Melanomas 1.0 mm or less in thickness, with possible ulceration
• T2: Melanomas 1.01–2.0 mm, with possible ulceration
• T3: Melanomas 2.01–4.0 mm, with possible ulceration
• T4: Melanomas more than 4.0 mm, with possible ulceration

Nodes (describes whether cancer has spread into the lymph nodes)

• NX: Lymph nodes cannot be examined.
• N0: No metastasis found in lymph nodes.
• N1: Metastases based on number of metastatic nodes and is present in one lymph node.
• N2: Metastasis present in 2 or 3 lymph nodes.
• N3: Metastasis is present in four or more lymph nodes.

Metastasis (describes the extent of cancer spread outside primary melanoma site)

• M0: No evidence of melanoma cells elsewhere in the body
• 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

Stage 0

Tis, N0, M0

Stage 1A

T1a, N0, M0

Stage 1B

T1b, N0, M0

T2a, N0, M0

Stage IIA

T2b, N0, M0

T3a, N0, M0

Stage IIB

T3b, N0, M0

T4a, N0, M0

Stage IIC

T4b, N0, M0

Stage IIIA

T1–4a, N1a, M0

T1–4a, N2a, M0

Stage IIIB

T1–4b, N1a, M0

T1–4b, N2a, M0

T1–4a, N1b, M0

T1–4a, N2b, M0

T1–4a, N2c, M0

Stage IIIC

T1–4b, N1b, M0

T1–4b, N2b, M0

T1–4b, N2c, M0

Any T, N3, M0

Stage IV

Any T, Any N, M1