Staging is the process of finding out how widespread the cancer is. This includes finding out how big it is and whether it has spread to the lymph nodes or any other organs. The tests described above are used to help decide the stage of the melanoma. Staging is very important because the treatment and the outlook (prognosis) for your recovery depend on the stage of the cancer.

Stages are labeled using 0 and the Roman numerals I through IV (1-4). In general, the lower the number, the less the cancer has spread. A higher number, such as stage IV (4), means a more serious cancer.

There are really 2 types of staging for melanoma. The clinical stage is based on what is found in the physical exam, biopsy, x-rays, CT scans, and so on. The pathological stage uses all of this information plus what is found during biopsies of lymph nodes or other organs. So the clinical stage (which is done first) may be lower than the pathologic stage, which is found after the biopsy.

After looking at your test results, the doctor will tell you the stage of your cancer. Be sure to ask your doctor to explain your stage in a way you understand. This will help you both decide on the best treatment for you.

Thickness of the melanoma

The thickness of the melanoma as seen in the skin biopsy is called the "T category." The thinner the melanoma, the better the outlook. For the most part, melanomas less than about 1/25 of an inch deep (about the size of a period or a comma) have a very small chance of spreading. Thicker melanomas have a greater chance of spreading. The thickness of the melanoma also guides the choice of treatment.

In one method of measuring the thickness of the melanoma, the doctor uses a device something like a small ruler. This is called the Breslow measurement. Another system describes the thickness of a melanoma in relation to layers of the skin instead of actually measuring it. The Clark level of a melanoma uses a scale of I to V (1-5) to describe which layers of the skin are involved. Higher numbers mean a deeper melanoma.

Most often, the Breslow measurement of thickness is used in staging the cancer. Sometimes, though, the Clark level shows that a melanoma is more advanced than it appears from the Breslow measurement. Because of this, both systems may be used to describe a melanoma.

In either system, the melanoma is said to have a worse prognosis if it is ulcerated; this means that there is no covering layer of skin.

Last Medical Review: 07/01/2008
Last Revised: 05/06/2009