The following stages are used for melanoma:
Stage 0 (Melanoma in Situ)
In stage 0, abnormal melanocytes are found in the epidermis.
These abnormal melanocytes may become cancer and spread into nearby normal tissue. Stage 0 is also called melanoma in situ.
Stage I
In stage I, cancer has formed. Stage I is divided into stages IA and IB.
Millimeters; drawing shows millimeters (mm) using everyday objects.
A sharp pencil point shows 1 mm, a new crayon point shows 2 mm, and a new pencil-top eraser shows 5 mm.
Millimeters (mm). A sharp pencil point is about 1 mm, a new crayon point is about 2 mm, and a new pencil eraser is about 5 mm.
Stage IA: The tumor is not more than 1 millimeter thick, with or without ulceration.
Stage IB: The tumor is more than 1 but not more than 2 millimeters thick, without ulceration.
Stage II
Stage II is divided into stages IIA, IIB, and IIC
Stage IIA: The tumor is either:
more than 1 but not more than 2 millimeters thick, with ulceration; or
more than 2 but not more than 4 millimeters thick, without ulceration.
Stage IIB: The tumor is either:
more than 2 but not more than 4 millimeters thick, with ulceration; or
more than 4 millimeters thick, without ulceration.
Stage IIC: The tumor is more than 4 millimeters thick, with ulceration.
Stage III
Stage III is divided into stages IIIA, IIIB, IIIC, and IIID.
Stage IIIA: The tumor is not more than 1 millimeter thick, with ulceration, or not more than 2 millimeters thick, without ulceration.
Cancer is found in 1 to 3 lymph nodes by sentinel lymph node biopsy.
Stage IIIB:
(1) It is not known where the cancer began or the primary tumor can no longer be seen, and one of the following is true:
cancer is found in 1 lymph node by physical exam or imaging tests; or
there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.
or
(2) The tumor is not more than 1 millimeter thick, with ulceration, or not more than 2 millimeters thick, without ulceration, and one of the following is true:
cancer is found in 1 to 3 lymph nodes by physical exam or imaging tests; or
there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.
or
(3) The tumor is more than 1 but not more than 2 millimeters thick, with ulceration, or more than 2 but not more than 4 millimeters thick, without ulceration, and one of the following is true:
cancer is found in 1 to 3 lymph nodes; or
there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.
Stage IIIC:
(1) It is not known where the cancer began, or the primary tumor can no longer be seen.
Cancer is found:
in 2 or 3 lymph nodes; or
in 1 lymph node and there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin; or
in 4 or more lymph nodes, or in any number of lymph nodes that are matted together; or
in 2 or more lymph nodes and/or in any number of lymph nodes that are matted together.
There are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.
or
(2) The tumor is not more than 2 millimeters thick, with or without ulceration, or not more than 4 millimeters thick, without ulceration.
Cancer is found:
in 1 lymph node and there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin; or
in 4 or more lymph nodes, or in any number of lymph nodes that are matted together; or
in 2 or more lymph nodes and/or in any number of lymph nodes that are matted together. There are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.
or
(3) The tumor is more than 2 but not more than 4 millimeters thick, with ulceration, or more than 4 millimeters thick, without ulceration.
Cancer is found in 1 or more lymph nodes and/or in any number of lymph nodes that are matted together.
There may be microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin
or
(4) The tumor is more than 4 millimeters thick, with ulceration.
Cancer is found in 1 or more lymph nodes and/or there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.
Stage IIID: The tumor is more than 4 millimeters thick, with ulceration.
Cancer is found:
in 4 or more lymph nodes, or in any number of lymph nodes that are matted together; or
in 2 or more lymph nodes and/or in any number of lymph nodes that are matted together.
There are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.
Stage IV
In stage IV, the cancer has spread to other parts of the body, such as the lung, liver, brain, spinal cord, bone, soft tissue (including muscle), gastrointestinal (GI) tract, and/or distant lymph nodes. Cancer may have spread to places in the skin far away from where it first started.