Staging is the process of determining how much cancer is present and where it is located. It then describes the severity of a malignancy based on the extent of the malignancy and whether it has spread to lymph nodes or other organs.
Recognizing the state of the disease allows the doctor to formulate a prognosis and to implement the most effective therapy based on the stage of the tumor
The American Joint Committee on Cancer (AJCC) TNM System
T (describes the tumor, its size and its extension within the skin):
- TX: the tumor cannot be studied
- T0: no evidence of the primary tumor
- T1s: Melanoma in situ (Clark level I)
- T1a: thickness less than or equal to 1 mm without ulceration and with Clark level II or III
- T1b: thickness less than or equal to 1 mm without ulceration and with Clark level IV or V or with ulceration
- T2a: thickness between 1.01 and 2.0 mm without ulceration
- T2b: thickness between 1.01 and 2.0 mm with ulceration
- T3a: thickness between 2.01 and 4.0 mm without ulceration
- T3b: thickness between 2.01 and 4.0 mm with ulceration
- T4a: thickness greater than 4 mm without ulceration
- T4b: thickness greater than 4 mm with ulceration
N (refers to regional lymph nodes and depends on whether the sentinel node was removed):
- NX: lymph nodes not investigated
- N0: no lymph node dissemination
- N1a: occult dissemination to 1 satellite lymph node
- N1b: dissemination to a clinically apparent lymph node
- N2a: dissemination to 2 or 3 satellite lymph nodes, or regional intralymphatic metastases without clinically occult nodal metastasis
- N2b: dissemination to 2 or 3 satellite lymph nodes, or regional intralymphatic metastases without clinically apparent nodal metastases
- N2c: satellitosis or metastasis in transit without lymph node location
- N3: dissemination to 4 or more regional lymph nodes, or metastasis in transit or satellitosis associated with lymph node metastases
Category M (refers to distant metastases).
- MX: distant metastases cannot be evaluated
- M0: no distant metastases
- M1a: distant metastases to the skin or subcutis or distant lymph nodes
- M1b: metastasis to lung
- M1c: metastasis to other organs or associated with high levels of LDH
Staging (SR – survival rate):
- Stage 0: Tis, N0, M0: melanoma in situ
- Stage IA: T1a, N0, M0: (SR: 99 %)
- Stage IB: T1b or T2a, N0, M0: (SR: 92 %)
- Stage IIA: T2b or T3a, N0, M0: (SR: 78 %)
- Stage IIB: T3b or T4a, N0, M0: (SR: 68%)
- Stage IIC: T4b, N0, M0: (SR: 56 %)
- Stage IIIA: T1a-4a, N1a or N2a, M0: (SR: not available)
- Stage IIIB: T1b-4b, N1a or N2a, M0 or T1a-4a, N1b or N2b, M0 or T1a/b-4a/b, N2c, M0: (SR: 50 %)
- Stage IIIC: T1b-4b, N1b or N2b, M0 or any T, N3, M0: (SR: 27 %)
- Stage IV: any T, any N, M1: (SR: 18 %)
