Skin Cancer Staging

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Staging is the process of finding out if cancer is localized or widespread. It will show if the cancer has spread to other body structures and, if so, how far. The treatment and prognosis (outlook for survival) for a patient with skin cancer depends, to a large extent, on the cancer’s stage.

About Staging

If a biopsy confirms that skin cancer is present, the doctor will determine the stage, or extent, of the disease before planning treatment. In general, there are two stages of skin cancer: local (affecting only the skin) or metastatic (spreading beyond the skin).

If the skin cancer is very large or has been present for a long time, the doctor will check the nearby lymph nodes and may order additional tests to find out if the cancer has spread to other parts of the body.

The most common system used to stage melanoma and non-melanoma is the TNM system.

  • T stands for tumor (its size and how far it has spread within the skin and to nearby tissues),
  • N stands for spread to lymph nodes (small bean-shaped collections of immune system cells that help the body fight infections and cancers), and
  • M is for metastasis (spread to distant organs). In TNM staging, information about the tumor, lymph nodes, and metastasis is combined according to a process called stage grouping to assign a stage. The stage is described in Roman numerals from I to IV. In general, patients with lower stage cancer have a better prognosis for a cure or long-term survival.

Stages

Stage 0 Melanoma:

The melanoma is in situ, meaning that it is found in the outer layer of skin only.

Stage I Melanoma:

The melanoma is less than 1 1/2 mm or about 1/16 inch in thickness. It appears to be localized in the skin, and has not been found in lymph nodes or distant organs.

Stage II Melanoma:

The melanoma has a thickness of greater than 1 1/2 mm (about 1/16 inch). It still appears to be localized to the skin and has not been found in lymph nodes or distant organs.

Stage III Melanoma:

The melanoma has spread to lymph nodes near the affected skin area.

Stage IV Melanoma:

The melanoma has spread beyond the original area of skin and the nearby lymph nodes to other organs such as the lung, liver, or brain, or to distant areas of the skin or lymph nodes.

Stage 0 Nonmelanoma:

Squamous cell carcinoma in situ, also called Bowen’s disease, is the earliest stage of squamous cell skin carcinoma. The cancer is found in the outer layer of skin only.

Stage I Nonmelanoma:

The cancer is not larger than 2 centimeters (between 3/4 and 7/8 inch) but it has not spread to lymph nodes or other organs.

Stage II Nonmelanoma:

The cancer is larger than 2 cm (centimeters) but it has not spread to lymph nodes or other organs.

Stage III Nonmelanoma:

The cancer has spread to tissues beneath the skin (such as muscle, bone, or cartilage) and/or it has spread to nearby lymph nodes. In this stage, the cancer has not spread to other organs such as the lungs or brain.

Stage IV Nonmelanoma:

The cancer can be any size. It has spread to other organs such as the lungs or brain.