Skin Cancer (Cutaneous Oncology) Program

Melanoma

What Is Melanoma? | Incidence and Risk Factors | Symptoms and Diagnosis | Stages | Treatment

Stages

If a skin biopsy shows that melanoma is present, the doctor will need to perform additional tests to find out whether the cancer cells have spread to other areas of the body. This process is known as staging, and it is important for determining treatment and outcomes.

There are several important factors that are used in staging melanoma:

Tumor thickness: Tumor thickness is one of the most important factors in staging melanoma. The thickness of the tumor is reported in millimeters, and melanomas are classified as being thin, intermediate, or thick based on this thickness measurement. Tumors that are ≤1.0 mm are called thin melanomas, tumors that are 1.01-4.0 mm are called intermediate thickness melanomas, and tumors that are >4.0 mm are called thick melanomas.

Ulceration: Melanoma lesions are said to be ulcerated or non-ulcerated depending on whether there is an intact superficial layer of skin (epidermis) over the lesion. For each tumor thickness, patients with ulcerated lesions will have a worse prognosis and are therefore placed in a higher stage.

Lymph nodes: If abnormal cells spread outside of the primary melanoma lesion, they most often go to the lymph nodes in the area of the tumor. Lymph nodes are small glands that are found all over the body and are involved in the body’s immune response. In the case of melanoma, both the number of lymph nodes with abnormal cells, as well as the amount of disease in the lymph nodes, is important for staging. When lymph nodes are involved, the patient has a worse prognosis and therefore, a higher stage of disease.

Metastases: This occurs when the abnormal cells have spread beyond the primary melanoma lesion and the lymph nodes draining the tumor to involve other organs and distant lymph nodes in the body.

Using information on tumor thickness, ulceration, lymph nodes, and metastases, patients can be staged.

Stage 0 (Melanoma in Situ): Abnormal cells are only identified in the upper layer of the skin (epidermis).

Stage I/II: Patients with stage I or II melanoma have disease in which abnormal cells are located only in one skin lesion and have not spread to lymph nodes draining the tumor or other distant sites. Outcomes for these patients are determined by the tumor thickness and whether or not the lesion is ulcerated.

Stage III: Patients with stage III melanoma have either abnormal cells that have spread to lymph nodes draining the tumor or abnormal cells that have developed into skin lesions outside the area of the primary skin lesion. Abnormal cells have not spread to other organs or distant lymph nodes.

Stage IV: Patients with stage IV melanoma have abnormal cells that have spread to distant organs or lymph nodes.


This page was last updated on: January 22, 2008.