Diagnosis and Staging

Melanoma

Melanoma is diagnosed based on biopsy. The main types of kin biopsy are shave, punch, incisional or excisional biopsy. Melanoma initially is staged is based on the depth of the tumor and certain pathologic features of the biopsied specimen. However, involvement of lymph nodes or distant sites may alter the staging. Risk of spread of cancer to the lymph nodes increases as the melanoma becomes thicker. Lymph node staging and biopsy may be required depending on the thickness of primary melanoma. Staging of melanoma is adopted from the AJCC 8th edition staging.  Mitotic rate was removed from the staging but remians prognostically significant.

T for primary tumor:

The T category is based on primary tumor thickness. 

  • Tx: Tumor cannot be evaluated.
  • T0: No evidence of cancer.
  • Tis: Melanoma in situ describes a cancer that is confined to the outer layer of the skin.
  • T1: Primary tumor depth is < 1.0mm
    • T1a: <0.8mm, no ulceration
    • T1b:   0.8-1mm with or wihtout ulceration
  • T2: Primary tumor depth is between 1.01 and 2.0mm
    • T2a: no ulceration
    • T2b: with ulceration
  • T3: Primary tumor depth is 2.01 to 4.0mm
    • T3a: no ulceration
    • T3b: with ulceration
  • T4: Primary tumor depth is > 4.0mm
    • T4a: no ulceration
    • T4b: with ulceration

N for regional lymph nodes:

The N category is determined by whether the cancer has spread to the lymph nodes.

  • Nx: Lymph nodes cannot be evaluated
  • N0: No evidence of cancer in the lymph nodes
  • N1: There are melanoma in one lymph node or intransit, satellite, and/or microsatellite metastases with no tumor involved nodes, further described by:
    • N1a: One clinically occult node (cannot be felt on physical exam), No satellite or in-transit metastases.
    • N1b: One clinically detected (can be felt by physical exam), No satellite or in-transit metastases.
    • N1c: No regional lymph node disease, but with satellite or in-transit metastases.
  • N2: There are melanoma cells in 2 or 3 lymph nodes, further described by:
    • N2a: 2 or 3 clinically occult (can be seen by microscope, but not felt by physical exam), No satellite or in-transit metastases,
    • N2b: Two or three, atleast one of which was clinicalldetected (can be felt by physical exam), No satellite or in-transit metastases,
    • N2c: One cliniclly occult or clinically detected, with in-transit or satellite lesions 
  • N3: Any of the following:
    • N3a: > or = 4 lymph nodes with melanoma cells, clinically not detected, No satellite or in-transit metastases,
    • N3b: 4 or more positive lymph nodes, at least one clinicalldetected or matted nodes, No satellite or in-transit metastases,
    • N3c:  Two or more clinically occult or clinically detected and/or presence of any matted noes with in transit or satellite metastases

M for distant metastasis:

The M category is used to describe melanoma spread to other sited in the body. 

  • Mx: metastases cannot be evaluated
  • M0: No evidence of metastases
  • M1a: the melanoma has spread from the primary site to other areas of the skin or under the skin, or distant lymph nodes
    • M1a (0), LDH not elevated (Lactate dehydrogenase)
    • M1a (1), LDH elevated
  • M1B: Melanoma has spread to the lung
    • M1b (0), LDH not elevated
    • M1b (1), LDH elevated
  • M1c: Distant metastate to other parts of the bode but not central nervous system (Brain), with or without M1a or M1b
    • M1c (0), LDH not elevated
    • M1c (1), LDH elevated
  • M1d: Distant metastate central nervous system (Brain), with or without M1a or M1b or M1c
    • M1d (0), LDH not elevated
    • M1d (1), LDH elevat

 

Staging Groups:

  • Stage 0
    • Tis, N0, M0: The melanoma is in situ, meaning that it is in the epidermis but has not spread to the dermis (lower layer).

 

  • Stage IA
    • T1a or T1b, N0, M0: The melanoma is less than 1.0 mm in thickness. It has not been found in lymph nodes or distant organs.

 

  • Stage IB
    • T2a, N0, M0:he melanoma is between 1.01 mm and 2.0 mm in thickness and is not ulcerated. It has not been found in lymph nodes or distant organs.

 

  • Stage IIA
    • T2b or T3a, N0, M0: The melanoma is between 1.01 mm and 2.0 mm in thickness and is ulcerated, OR it is between 2.01 and 4.0 mm and is not ulcerated. It has not been found in lymph nodes or distant organs.

 

  • Stage IIB
    • T3b or T4a, N0, M0: The melanoma is between 2.01 mm and 4.0 mm in thickness and is ulcerated, OR it is thicker than 4.0 mm and is not ulcerated. It has not been found in lymph nodes or distant organs.

 

  • Stage IIC
    • T4b, N0, M0: The melanoma is thicker than 4.0 mm and is ulcerated. It has not been found in lymph nodes or distant organs.

 

  • Stage IIIA
    • T1a/b to T2a, N1a or N2a, M0: Melanoma less than 1mm with or without ulceration and melanoma that is less than 2mm without ulceration. It has spread to 1 to 3 lymph nodes near the affected skin area, but the nodes are not enlarged and the melanoma is found only when they are viewed under the microscope. There is no distant spread.

 

  • Stage IIIB
    • T0, N1b or N1c: There is no distant spread.
    • T1a/b-T2a, N1b/c or N2b, M0: There is no distant spread.
    • T2b to T3a, N1a-N2b, M0: There is no distant spread.

 

  • Stage IIIC
    • T1a/b, N2c or N3a/b/c, M0: There is no distant spread.
    • T3b to T4a, Any N grater or equal to N1, M0:  There is no distant spread.
    • T4b, N1a-N2c, M0:  There is no distant spread.

 

  • Stage IIID
    • T4b, N3a/b/c, M0: There is no distant spread 

 

  • Stage IV
    • Any T, any N, M1(a, b, C or d): The melanoma has spread beyond the original area of skin and nearby lymph nodes to other organs such as the lung, liver, or brain, or to distant areas of the skin, subcutaneous tissue, or distant lymph nodes. Neither spread to nearby lymph nodes nor thickness is considered in this stage, but typically the melanoma is thick and has also spread to the lymph nodes.