What Are the Stages of Melanoma?
Staging of a cancer provides a way to describe a tumor and whether and how far it has spread. The higher the stage number, the more widespread is the cancer. These stages are used to determine the type of treatment for melanoma.
A number of staging systems have been developed for melanoma. The two most commonly used systems are based on clinical staging and pathologic staging. Clinical staging uses the results of a physical exam, biopsies, and any imaging studies (e.g., CT scan or x-ray). Pathologic staging uses this information in addition to the results of biopsies of lymph nodes and/or other organs.
The TNM System
Once a biopsy has been performed, a tool called the TNM (tumor, node, metastasis) system can be used to determine the stage of melanoma. This system is not a staging system in itself; rather, it is used to define the characteristics of the tumor so that the stage can then be determined.
The TNM system uses three criteria: the tumor itself, the lymph nodes near the tumor (regional lymph nodes), and whether (and how far) the tumor has spread to the rest of the body. The results are combined to determine the stage of cancer for each person.
In the TNM system for melanoma, the “T” indicates the thickness of the tumor:
Tx: The primary, or original, tumor cannot be evaluated because of incomplete information.
T0: There is no evidence of cancer in the tissue sample.
Tis: Melanoma cells are present in the tissue sample, but are less than 0.1 millimeter thick.
T1: The tumor is 0.1 to 1.0 millimeter thick.
T2: The tumor is 0.10 to 2.0 millimeters thick.
T3: The tumor is 2.01 to 4.0 millimeters thick.
T4: The tumor is more than 4.0 millimeters thick.
The “N” in the TNM staging system indicates the results of the sentinel node biopsy described earlier:
Nx: The regional nodes cannot be assessed because of incomplete information.
N0: There is no evidence of cancer in the regional lymph nodes.
N1: Cancer cells have been found in one node.
N2: Cancer cells have been found in two or three nodes.
N3: Cancer cells have been found in four or more nodes.
The “M” in the TNM system refers to distant metastases—whether, and how far, the cancer has spread outside the original site:
Mx: Distant metastases cannot be evaluated because of incomplete information.
M0: There is no evidence that the cancer has spread beyond the original site.
M1: The cancer has spread beyond the original site:
M1a: The cancer has spread to other areas of skin, underneath the epidermis to the dermis (subcutaneous), or to lymph node(s).
M1b: The cancer has spread to the lung(s).
M1c: The cancer has spread to other organs and/or locations in the body.
Staging of Melanoma
The TNM system is used to determine the stage of melanoma:
|
American Joint Committee on Cancer (AJCC) Melanoma System
|
| Stage |
TNM
|
Characteristics
|
|
Stage 0
|
Tis
N0
M0
|
In situ melanoma. The cancer is limited to the outermost layers of the skin, the epidermis (Tis). There is no evidence that the cancer has spread to the lymph nodes (N0) or to distant organs (M0). |
|
Stage I:
IA
|
T1a
N0
M0
|
The tumor is 1 millimeter thick or less (T1), the surface is not ulcerated (broken) (a), and the tumor extends beneath the epidermis to the dermis. There is no evidence that the cancer has spread to the lymph nodes (N0) or to distant organs (M0). |
|
IB
|
T1b, T2a
N0
M0
|
The tumor is 1 millimeter thick or less (T1) but has ulcerated (b), or it is between 1.01 and 2 millimeters thick (T2) but has not ulcerated (a). There is no evidence that the cancer has spread to the lymph nodes (N0) or to distant organs (M0). |
|
Stage II:
IIA
|
T2b, T3a
N0
M0
|
The tumor is between 1.01 and 2.0 millimeters thick (T2) and has ulcerated (b) or is between 2.01 and 4 millimeters thick (T3) and has not ulcerated (a). There is no evidence that the cancer has spread to the lymph nodes (N0) or to distant organs (M0). |
| IIB |
T3b, T4a
N0
M0
|
The tumor is between 2.01 and 4 millimeters thick (T3) and has ulcerated (b) or is 4 millimeters thick or greater (T4) and has not ulcerated (a). There is no evidence that the cancer has spread to the lymph nodes (N0) or to distant organs (M0). |
| IIC |
T4b
N0
M0
|
The tumor is 4 millimeters thick or greater (T4) and has ulcerated (b). There is no evidence that the cancer has spread to the lymph nodes (N0) or to distant organs (M0). |
Stage III:
IIIA |
T1-4a
N1a, N2a
M0
|
The tumor is between 1 and 4 millimeters thick or greater (T1-4) and has not ulcerated (a). There is evidence that the cancer has spread to one regional lymph node (N1) or to two to three regional nodes (N2). Stage N2a cancer is less severe than stage N2b or N2c cancer. There is no evidence that the cancer has spread to distant organs (M0). At this stage, the thickness of tumor is no longer the most important prognostic indicator. |
| IIIB |
Any T
N1a-N2c
M0
|
The tumor may be any thickness (T) and may (b) or may not (a) have ulcerated. There is evidence that the cancer has spread to one or more lymph nodes (N1-2). There is no evidence that the cancer has spread to distant organs (M0). |
| IIIC |
Any T
Any N (except 0)
M0
|
The tumor may be any thickness and has ulcerated. There is evidence that the cancer has spread to one or more lymph nodes (N). There is no evidence that the cancer has spread to distant organs (M0). |
|
Stage IV
|
Any T
Any N (except 0)
M1a, M1b, M1c
|
The tumor may be any thickness. There is evidence that the cancer has spread to one or more lymph nodes (N), and the melanoma has metastasized (M1) to other organs (a = distant skin and subcutaneous tissue; b = lungs; c = all other distant organs, e.g., liver or brain). Prognosis is poor. |
Adapted from: SkinCancerNet. Staging: The First Step in Treating Skin Cancer. Available at http://www.skincarephysicians.com/skincancernet/staging.html. Retrieved April 30, 2007.
This content was last modified on
June 22, 2007
.