Melanoma

Microstages of Melanoma

Staging is a process to determine the extent of cancer. The staging of melanoma is more complex than that of basal cell or squamous cell skin cancers. More detailed information about the melanoma is required to accurately determine the stage of the cancer.

Microstaging of melanoma helps provide the additional information to determine how thick the tumor is, how deep it has invaded the skin, the level of the tumor’s ulceration and if cancer cells have spread to lymph nodes or other organs of the body. After your healthcare provider has this vital information, it’s used to plan the most effective course of treatment.


Melanoma TNM Classification
 T
 Classification
 Thickness  Ulceration Status
 T1  ≤1.0 mm  a: Without ulceration 
 and level II/III
 b: With ulceration or 
 level IV/V
 T2  1.01 - 2.0 mm  a: Without ulceration
 b: With ulceration
 T3  2.01 - 4.0 mm  a: Without ulceration
 b: With ulceration
 T4  >4.0 mm  a: Without ulceration
 b: With ulceration
 N
 Classification 
 Number of 
 Metastatic Nodes
 Nodel Metastatic
 Mass
 N1  1 node  a:Micrometastasis*
 b:Macrometastasis**
 N2  2 - 3 nodes  a:Micrometastasis*
 b:Macrometastasis**
 c: In-transit met
 (s)/satellite(s)+
 N3  4 or more metastatic nodes, matted nodes or in-transit met(s) / satellite(s) + with metastatic node(s)  
 M
 Classification
 Site  Serum Lactate
 Dehydrogenase 
 M1a  Distant skin, subcutaneous or nodal metastases  Normal
 M1b  Lung metastases  Normal
 M1c  All other visceral metastases
 Any distant metastasis
 Elevated

*Micrometastases are diagnosed after sentinel or elective lymphadenectomy.

**Macrometastases are defined as clinically detectable nodal metastases confirmed by therapeutic lymphadenectomy or when nodal metastasis exhibits gross extracapsular extension.

+In-transit metastases are >2 cm from the primary tumor but not beyond the regional lymph nodes, while satellite lesions are within 2 cm of the primary.


Stage Groupings for Cutaneous Melanoma
  Survival (%)*   Clinical Staging**     Pathologic Staging+  
     T  N  M  T  N  M
 0    Tis  N0  M0  Tis  N0  MO
 IA  95  T1a  N0  M0  T1a  N0  MO
 IB  90  T1b
 T2a
 N0  M0  T1b
 T2a
 N0  MO
 IIA  78  T2b
 T3a
 N0  M0  T2b
 T3a
 N0  MO
 IIB  65  T3b
 T4a
 N0  M0  T3b
 T4a
 N0  MO
 IIC  45  T4b  N0  M0  T4b  N0  MO
 III++    AnyT  N1
 N2
 N3
 M0      
 IIIA  66        T1-4a
 T1-4a
 N1a
 N2a
 MO
 IIIB  52        T1-4b
 T1-4b
 T1-4a
 T1-4a
 T1-
 4a/b
 N1a
 N2a
 N1b
 N2b
 N2c
 MO
 IIIC  26        T1-4b
 T1-4b
 Any T
 N1b
 N2b
 N3
 M0
 IV  7.5 - 11  Any
 T
 Any N  AnyM1  Any T  Any N  AnyM1

*Approximate five-year survival (%), modified from Balch et al.

**Clinical staging includes microstaging of the primary melanoma and clinical/radiologic evaluation for metastases. By convention, it should be used after complete excision of the primary melanoma with clinical assessment for regional and distant metastases.

+Pathologic staging includes microstaging of the primary melanoma and pathologic information about the regional lymph nodes after partial or complete lymphadenectomy. Pathologic stage 0 or stage IA patients are the exception.

++There are no stage III subgroups for clinical staging.


Major Independent Prognostic Factors for Survival in Multivariate Analyses
 Prognostic
 Factor
 Commentary
 Tumor thickness  ≤1 mm low risk, >1 mm higher risk melanoma
 Ulceration  Worse prognosis with ulceration
 Age  Higher age with worse prognosiss
 Sex  Only for localized disease, males with poorer prognosis
 Anatomic site  Trunk, head and neck with poorer prognosis than extremities
 Number of
involved
lymph nodes
 Cut-off points: 1, 2 – 3, 4 or more lymph nodes
 Regional  lymph node tumor burden  Macroscopic (palpable) nodal metastases with poorer prognosis than microscopic (non-palpable) nodal metastases 
 Site of distant
metastases
 Visceral metastases with poorer prognosis than non-visceral (skin, subcutaneous distant lymph nodes)

 

Surgical Treatment of Primary Melanoma
 Thickness  Excision
 margins
 (cm)
 Comments
 In situ  0.5  No randomized studies; lentigo maligna of the face might be treated with radiotherapy in specialized centers
 <1 mm  1.0  AAD task force suggests a 1 cm margin for melanomas <2 mm
 1 - 4 mm  2.0  AAD task force suggests a 2 cm margin for melanomas ≥2 mm
 >4 mm  2.0 - 3.0  No randomized studies


These tables were published in Dermatology, Vol 2, Jean L. Bolognia et al, Pages 1759 – 1761, © Elsevier Ltd., (2008). Used by permission: Elsevier Ltd., Oxford, UK.