If the diagnosis is melanoma, the doctor needs to learn the extent, or stage, of the disease before planning treatment. Staging is a careful attempt to learn how thick the tumor is, how deeply the melanoma has invaded the skin, and whether melanoma cells have spread to nearby lymph nodes or other parts of the body. The doctor may remove nearby lymph nodes to check for cancer cells. (Such surgery may be considered part of the treatment because removing cancerous lymph nodes may help control the disease.) The doctor also does a careful physical exam and, if the tumor is thick, may order chest X-rays, blood tests, and scans of the liver, bones, and brain.
The following stages are used for melanoma:
- Stage 0: In stage 0, the melanoma cells are found only in the outer layer of skin cells and have not invaded deeper tissues.
- Stage I: Melanoma in stage I is thin:
- The tumor is no more than 1 millimeter (1/25 inch) thick. The outer layer (epidermis) of skin may appear scraped. (This is called an ulceration).
- Or, the tumor is between 1 and 2 millimeters (1/12 inch) thick. There is no ulceration. The melanoma cells have not spread to nearby lymph nodes.
- Stage II: The tumor is at least 1 millimeter thick:
- The tumor is between 1 and 2 millimeters thick. There is ulceration.
- Or, the thickness of the tumor is more than 2 millimeters. There may be ulceration. The melanoma cells have not spread to nearby lymph nodes.
- Stage III: The melanoma cells have spread to nearby tissues:
- The melanoma cells have spread to one or more nearby lymph nodes.
- Or, the melanoma cells have spread to tissues just outside the original tumor but not to any lymph nodes.
- Stage IV: The melanoma cells have spread to other organs, to lymph nodes, or to skin areas far away from the original tumor.
- Recurrent: Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may have come back in the original site or in another part of the body.