Radiation Oncology/Melanoma/Staging

Melanoma Staging

Clark Levels

 * Level I - Confined to epidermis (in situ); not an invasive lesion
 * Level II - Invasion of papillary dermis; invasion past basement membrane
 * Level III - Papillary dermis filled by tumor and reticular dermis compressed, but not invaded
 * Level IV - Invasion of reticular dermis; subcutaneous tissue not involved
 * Level V - Invasion of subcutaneous tissue


 * Univ Pennsylvania; 1989 PMID 2593166 -- "Model predicting survival in stage I melanoma based on tumor progression." (Clark WH Jr, J Natl Cancer Inst. 1989 Dec 20;81(24):1893-904.)
 * Prognostic model for primary, clinical Stage I cutaneous melanoma. Clark levels defined

Current staging
AJCC 7th Edition (2009) Primary Tumor: (Based on thickness, not level of invasion)


 * Tis - melanoma in situ (epidermis only)
 * T1 - <= 1.0 mm in thickness
 * T1a - no ulceration; mitotic rate < 1/mm2
 * T1b - with ulceration or mitotic rate >= 1/mm2
 * T2 - 1.01 - 2 mm in thickness
 * T2a - no ulceration
 * T2b - with ulceration
 * T3 - 2.01 - 4 mm in thickness
 * T3a - no ulceration
 * T3b - with ulceration
 * T4 - > 4 mm in thickness
 * T4a - no ulceration
 * T4b - with ulceration

Regional Lymph Nodes:
 * N0 - no nodes
 * N1 - 1 positive lymph node
 * N1a - micrometastasis
 * N1b - macrometastasis
 * N2 - 2-3 nodes or intralymphatic regional metastasis without nodal metastasis
 * N2a - micrometastasis
 * N2b - macrometastasis
 * N2c - satellite or in-transit metastasis without nodal metastasis
 * N3 - 4 or more nodes, or matted metastatic nodes, or satellite/in-transit metastases with nodal mets

Satellite metastases: defined as grossly visible cutaneous or subcutaneous intralymphatic metastases occurring within 2 cm of primary melanoma Microsatellites: any discontinuous nest of intralymphatic metastatic cells >0.05 mm in diameter that are clearly separated from the main invasive lesion by a distance of at least 0.3 mm In-transit metastases: grossly visible cutaneous or subcutaneous intralymphatic metastases more than 2 cm from primary melanoma but before the first echelon of regional lymph nodes

Distant Metastases:
 * M1a - metastasis to skin, subcutaneous tissues, or distant lymph nodes
 * M1b - metastasis to lung
 * M1c - all other visceral sites, or mets to any site with elevated LDH

Clinical Stage Grouping: Clinical staging is based on information from excision of the melanoma and clinical evaluation for distant metastatic disease but does not include lymphadenectomy
 * 0 - Tis
 * IA - T1a N0
 * IB - T2a or T1b N0
 * IIA - T3a or T2b N0
 * IIB - T4a or T3b N0
 * IIC - T4b N0
 * III - Any N+
 * IV - Any M1
 * Note: ulceration (b) upstages by one grouping

Pathologic Stage Grouping: Includes information obtained from lymphadenectomy Same as clinical staging except for Stage III
 * IIIA - N1a or N2a (micrometastasis), no ulceration (T1-4a)
 * IIIB - N1b or N2b or N2c (micromets or satellite), no ulceration (T1-4a); N1a or N2a (micromets), with ulceration (T1-4b)
 * IIIC - N1b or N2b or N2c (micromets or satellite), with ulceration (T1-4b); or any N3

Changes from 6th Edition:
 * T-stage: T1a vs T1b now includes mitotic rate in addition to ulceration; eliminated use of Clark level. T2-T4 unchanged.
 * No changes in N-stage or M-stage
 * No changes in Stages I or II.
 * No changes in Clinical Stage III
 * For Pathologic Stage III, N2c with ulceration reclassified from IIIB to IIIC

Older staging systems
AJCC 6th Edition (2002)

T-stage: (Based on thickness, not level of invasion, except for T1 melanomas) N-stage: M-stage:
 * Tis - melanoma in situ (epidermis only)
 * T1 - <= 1.0 mm in thickness
 * T1a - Clark level II or III, no ulceration
 * T1b - Clark level IV or IV or with ulceration
 * T2 - 1.01 - 2 mm in thickness
 * T2a - no ulceration
 * T2b - with ulceration
 * T3 - 2.01 - 4 mm in thickness
 * T3a - no ulceration
 * T3b - with ulceration
 * T4 - > 4 mm in thickness
 * T4a - no ulceration
 * T4b - with ulceration
 * N0 - no nodes
 * N1 - 1 positive lymph node
 * N1a - clinically occult (microscopic)
 * N1b - clinically apparent (macroscopic)
 * N2 - 2-3 nodes or intralymphatic regional metastasis without nodal metastasis
 * N2a - microscopic
 * N2b - macroscopic
 * N2c - satellite or in-transit metastasis without nodal metastasis
 * N3 - 4 or more nodes, or matted metastatic nodes, or satellite/in-transit metastases with nodal mets
 * M1a - metastasis to skin, subcutaneous tissues, or distant lymph nodes
 * M1b - metastasis to lung
 * M1c - all other visceral sites, or mets to any site with elevated LDH

Clinical stage grouping: Clinical staging is based on information from excision of the melanoma and clinical evaluation for distant metastatic disease but does not include lymphadenectomy
 * 0 - Tis
 * IA - T1a N0
 * IB - T2a or T1b N0
 * IIA - T3a or T2b N0
 * IIB - T4a or T3b N0
 * IIC - T4b N0
 * III - Any N+
 * IV - Any M1
 * Note: ulceration (b) upstages by one grouping

Pathologic stage grouping: Includes information obtained from lymphadenectomy Same as clinical staging except for Stage III
 * IIIA - N1a or N2a, no ulceration (T1-4a)
 * IIIB - N1b or N2b, no ulceration (T1-4a); N1a or N2a, with ulceration (T1-4b); or any N2c
 * IIIC - N1b or N2b, with ulceration (T1-4b); or any N3

Satellite metastases: defined as intralymphatic metastases occurring within 2 cm of primary melanoma In-transit metastases: more than 2 cm from primary melanoma but before the first echelon of regional lymph nodes

AJCC 5th edition (1997) T stage was based primary on Clark level of invasion. Used Breslow thickness as a secondary prognostic factor: with different thresholds of 0.75, 1.5, and 4 mm. Did not include ulceration. Satellite mets were in the T-stage. Thick (>4mm) melanomas were Stage III, not IIC. For N-stage used size not number of mets. Did not use microscopic vs macroscopic. Did not have separate M stage for lung mets. Did not use LDH.

Survival
10-year OS: (estimated from graph, AJCC staging manual)
 * Stage IA: 90%, IB: 80%
 * Stage IIA: 65%, IIB: 50%, IIC: 35%
 * Stage III: 35%
 * Stage IV: < 10%