Melanoma

Staging Becomes the Foundation of Your Treatment Plan

Once your diagnosis is made, a process called staging is used to determine the extent of the cancer within your body. This section is designed to help you better understand how staging enables your doctor to select the treatment options that will be most effective for you.

Melanoma is usually staged twice. First, your doctor considers the results of your physical exam and skin biopsy to assign a clinical stage. During a more extensive procedure, the lesion (or as much of it as possible) is removed along with some healthy tissue surrounding it. In a different procedure, some lymph nodes may be removed. After reviewing these specimens with and without a microscope and noting key characteristics, a pathologist also considers results from lymph node biopsies and other tissue that was examined. Then a pathologic stage is assigned. Because the pathologic stage is based on more details about the melanoma, this staging is the most accurate and is important in determining the best treatment options for your diagnosis.

Both the clinical and pathologic stages of melanoma are classified according to the tumor, node, metastasis (TNM) system developed by the American Joint Committee on Cancer (AJCC). This system uses the size and location of the tumor (T), whether cancer cells are found in nearby lymph nodes (N) and whether the cancer has metastasized, or spread, to other parts of the body (M). The thickness of the primary melanoma is used to classify the melanoma in the T category. Additionally, each T classification is further divided into groups according to whether ulceration (a break in the outer layer of skin over the melanoma) is absent (subcategory a) or present (subcategory b). The node (N) classification is used to describe how many lymph nodes contain melanoma cells and includes subcategories to describe the extent of cancer cells in the lymph nodes.

The results of the TNM analysis are then used to determine the overall stage of melanoma for each individual. Stages range from 0 to IV (see Tables 1 and 2).

Table 1 - AJCC TNM System for Classifying Melanoma of the skin

Classification Definition
Tumor (T)
T Category Thickness Ulceration Status
TX Primary tumor cannot be assessed  Not applicable
T0 There is no evidence of primary tumor Not applicable
Tis Melanoma in situ Not applicable
T1
  T1a
  T1b
≤ (not more than) 1.0 mm.
< (less than) 0.8 mm.
< (less than) 0.8 mm.
< 0.8 – 1.0 mm.
Unknown or unspecified
Without ulceration
With ulceration
With or without ulceration
T2
  T2a
  T2b
> (more than) 1.0 – 2.0 mm.
> (more than) 1.0 – 2.0 mm.
> (more than) 1.0 – 2.0 mm.
Unknown or unspecified
Without ulceration
With ulceration
T3
  T3a
  T3b
> (more than) 2.0 – 4.0 mm.
> (more than) 2.0 – 4.0 mm.
> (more than) 2.0 – 4.0 mm.
Unknown or unspecified
Without ulceration
With ulceration
T4
  T4a
  T4b
> (more than) 4.0 mm.
> (more than) 4.0 mm.
> (more than) 4.0 mm.
Unknown or unspecified
Without ulceration
With ulceration
Node (N)
N Category Number of tumor-involved regional lymph nodes Metastases status*
NX Regional nodes not assessed. No
N0 No regional metastases detected. No
N1
 

  N1a
  N1b
  N1c
One tumor-involved node or in-transit, satellite, and/or microsatellite metastases with no tumor-involved nodes.
One clinically occult.
One clinically detected.
No regional lymph node disease.
 
 

No
No
Yes
N2
 

  N2a
  N2b
 
  N2c
Two or three tumor-involved nodes or in-transit, satellite, and/or microsatellite metastases with one tumor-involved node.
Two or three clinically occult.
Two or three, at least one of which was clinically detected.
One clinically occult or clinically detected.



No
No

Yes
N3
 
 

  N3a
  N3b
 
  N3c
Four or more tumor-involved nodes or in-transit, satellite, and/or microsatellite metastases with two or more tumor-involved nodes, or any number of matted nodes without or with in-transit, satellite, and/or microsatellite metastases.
Four or more clinically occult.
Four or more, at least one of which was clinically detected, or presence of any number of matted nodes.
Two or more clinically occult or clinically detected and/or presence of any number of matted nodes.




No
No

Yes
* In-transit metastases occur more than 2 cm from the primary melanoma (both on the surface of the skin or below the surface of the skin) to the regional lymph nodes. Satellite metastases occur on or below the skin within 2 cm of the primary melanoma. Microsatellite metastases in the skin or in the deeper layer of the dermis near or deep within the skin of the primary melanoma is detected upon microscopic examination.
Metastasis (M)
M Category* Anatomic site LDH level
M0 No evidence of distant metastasis. Not applicable
M1
  M1a
      M1a(0)
      M1a(1)
  M1b
      M1b(0)
      M1b(1)
  M1c
      M1c(0)
      M1c(1)
  M1d
      M1d(0)
      M1d(1)
Evidence of distant metastasis.
Distant metastasis to skin, soft tissue including muscle, and/or nonregional lymph node.

Distant metastasis to lung with or without M1a sites of disease.

Distant metastasis to non-CNS visceral sites with or without M1a or M1b sites of disease.

Distant metastasis to CNS with or without M1a, M1b, or M1c sites of disease.

See below
Not recorded or unspecified
Not elevated
Elevated
Not recorded or unspecified
Not elevated
Elevated
Not recorded or unspecified
Not elevated
Elevated
Not recorded or unspecified
Normal
Elevated
*Suffixes for M category: (0) LDH not elevated, (1) LDH elevated. No suffix is used if LDH is not recorded or is unspecified.

Table 2 - Stages of Melanoma of the Skin

Stage T N M
0 Tis N0 M0
IA T1a
T1b
N0
N0
M0
M0
IB T2a N0 M0
IIA T2b
T3a
N0
N0
M0
M0
IIB T3b
T4a
N0
N0
M0
M0
IIC T4b N0 M0
IIIA T1a/b-T2a N1a or N2a M0
IIIB T0
T1a/b-T2a
T2b/T3a
N1b, N1c
N1b/c or N2b
N1a-N2b
M0
M0
M0
IIIC T0
T1a-T3a
T2b/T4a
T4b
N2b, N2c, N3b or N3c
N2c or N3a/b/c
Any N ≥ N1
N1a-N2c
M0
M0
M0
M0
IIID Any T, Tis Any N M0
IV Any T, Tis Any N M1
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original and primary source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer Science+Business Media.

More About Your Pathology Report

With today’s emphasis on personalizing treatment for each person’s cancer, including its genomic or molecular abnormalities, pathology report results are integral to melanoma treatment. Doctors have more options for treating melanoma by subtype now that drug therapies are available for targeting specific mutations, but these therapies can only be used if they are confirmed with genomic or molecular testing.

Along with your diagnosis and histologic subtype (classification based on the melanoma’s microscopic features), your pathology report may include some or all of the following:

Thickness: how deep the tumor has grown into the skin

Ulceration status: whether the tumor’s top skin layer is present and intact (not ulcerated) or broken or missing (ulcerated)

Dermal mitotic rate: how many melanoma cells are actively growing and dividing

Peripheral margin status: the presence or absence of cancer cells in the normal-looking tissue that was removed from around the tumor

Deep margin status: the presence or absence of cancer cells in the normal-looking tissue that was removed from underneath the tumor

Microsatellitosis: the presence of tiny satellite tumors that have spread to skin near the first melanoma tumor. These can only be seen with a microscope.

Regression: the presence of lymphocytes (a type of white blood cell) and scar-like changes that suggest a person’s immune system is attacking the melanoma

Location: where the tumor is found

Tumor-infiltrating lymphocytes: the presence of white blood cells that may be present in a primary melanoma

Vertical growth phase: evidence of tumor growth down into the skin

Angiolymphatic invasion: whether melanoma has grown into blood or lymph vessels

Neurotropism: the presence of melanoma cells in or around the nerves in the skin

Ask your doctor to explain how these findings affect your treatment options. You can also request a copy of your pathology report.

 

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