Melanoma of the Skin – AJCC 8th Edition Staging Spotlight


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Melanoma of the Skin can be found in the AJCC 8th Edition Staging Manual in Chapter 47, pages 563-581.  A review of Melanoma Staging is provided below with explanations on what has changed from the AJCC 7th Edition to the AJCC 8th Edition.  

Definition of Primary Tumor (T):

  1. Tumor thickness ranges are maintained, but T1 is subcategorized beginning at 0.8mm in depth.
  2. Ulceration is still an important part of T staging
    1. a = without ulceration
    2. b = ulcerated
  3. Mitotic rate is no longer utilized as staging criterion, but is still important & should continue to be recorded.
    1. T1a = nonulcerated, <0.8mm depth
    2. T1b = 0.8-1.0mm depth regardless of ulceration OR ulcerated <0.8mm depth

Definition of Regional Lymph Nodes (N):

  1. Previously used descriptors, “microscopic” and “macroscopic” have been redefined as “clinically occult” (clinical Stage I-II) and “clinically detected” (clinical Stage III).
  2. Non-nodal regional disease has been subcategorized in the N-category; microsatellites, satellites (w/in 2cm of primary tumor), and in-transit mets (greater than 2cm from primary) are now categorized as N1c, N2c, or N3c according to the number of tumor-involved regional lymph nodes, if there are any.
  3. Lymphoscintigraphy is important, as melanomas can drain to separate lymph node basins.

Definition of Distant Metastasis (M):

  1. M1 is categorized according to the anatomic site and the LDH value; 0 = not elevated, 1 = elevated.  (ex. Skin/soft tissue/nodal mets w/elevated LDH = M1a(1)
  2. New M1d added which includes mets to CNS with or w/o any other distant sites.
  3. Elevated LDH does not define M1c category anymore.

AJCC Prognostic Stage Groups:

  1. No overall change to T subcategories, however, they were refined and split into T1a vs T1b, according to tumor thickness under or over the 0.8mm threshold and ulceration.
  2. N category now has four stage groups instead of just three (T4bN3a/b/c/d).

Clarification on Stage IV not being further stage grouped: M1c = Stage IV, not Stage IVC

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