Overview of Stages 0-IV
Stages are labeled using 0 and Roman numerals I through IV (1-4).
A lower number like one (I) means the melanoma has not spread far.
The higher the number, the farther it has spread and the more serious the cancer.
Stage 0 Melanoma
In Stage 0 melanoma, the malignant tumor is still confined to the upper layers of the skin. This means that the cancer cells are only in the outer layer of the skin and have not grown any deeper. The term for this is in situ, which means "in place" in Latin. There is no evidence the cancer has spread to the lymph nodes or distant sites (metastasis).
Stage I Melanoma
Stage I melanoma is defined as a melanoma that is up to 2mm thick. A Stage I melanoma may or may not have ulceration. There is no evidence the cancer has spread to lymph nodes or distant sites (metastasis). There are two subclasses of Stage I Melanoma: 1A, 1B.
Stage II Melanoma
Stage II melanoma is defined by tumor thickness, and ulceration. There is no evidence the cancer has spread to the lymph nodes or distant sites (metastasis). There are three subclasses of Stage II: IIA, IIB, IIC.
Stage III Melanoma
Stage III melanoma is defined by the level of lymph node involvement and ulceration. In Stage III melanoma, the depth of the melanoma no longer matters.There is no evidence the cancer has spread to distant sites (metastasis). There are three
subclasses of Stage III Melanoma: IIIA, IIIB, IIIC.
Stage IV Melanoma
Stage IV melanoma occurs when the melanoma has spread beyond the original site and regional lymph nodes to more distant areas of the body. The level of LDH (serum lactate dehydrogenase) may or may not be elevated. The most common sites of metastasis are to vital organs (lungs, abdominal organs, brain, and bone) and soft tissues (skin, subcutaneous tissues) and distant lymph nodes (lymph nodes beyond the primary tumor region).
The following factors determine the stage of melanoma:
- Tumor thickness.
- Whether the tumor is with or without ulceration.
- Mitotic Count.
- Number of metastatic lymph nodes.
- Whether the metastasis is microscopic (tiny tumors not visible to naked eye) or macroscopic (tumors large enough to be visible or that can be felt).
- Site of distant metastasis: skin vs other areas.
- Level of LDH (serum lactate dehydrogenase).