# Radiation Oncology/Melanoma/Staging

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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)
* 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
N-stage:
* 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
M-stage:
* 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%