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Staging Melanoma
TNM Staging System
The TNM System (tumor-node-metastasis) is the most widely used system for cancer staging in the world. Created by the American Joint Committee on Cancer (AJCC), a distinguished group of experts from national healthcare organizations and major cancer centers around the country, the system defines cancer stage by describing:
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T: the features of the primary tumor. The three distinguishing features are tumor thickness, mitoses, and ulceration. Tumor thickness (also known as Breslow depth) is measured in millimeters (mm).
- 1 mm = .04 inch, or less than 1/16 inch (about equal to the edge of a penny)
- 2 mm = between 1/16 and 1/8 inch (about equal to the edge of a nickel)
- 4 mm = between 1/8 and 1/4 inch (about equal to the edges of two nickels)
N: the presence or absence of tumor spread to nearby lymph nodes
M: the presence or absence of metastasis to distant sites
Revised TNM Classification
This classification system was updated in 2009 by the AJCC.
| T Classification |
Thickness |
Ulceration Status |
| Tis |
N/A |
N/A |
| T1 |
≤ 1.0mm |
a: w/o ulceration and mitosis < 1 / mm2
b: with ulceration and mitosis ≥ 1 / mm2
|
| T2 |
1.01-2.0mm |
a: w/o ulceration
b: with ulceration
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| T3 |
2.01-4.0mm |
a: w/o ulceration
b: with ulceration
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| T4 |
> 4.0mm |
a: w/o ulceration
b: with ulceration
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| N Classification |
# of Metastatic Nodes |
Nodal Metastatic Mass |
| N0 |
No evidence of lymph node metastasis |
| N1 |
1 node |
a: micrometastasis
b: macrometastasis
|
| N2 |
2-3 nodes |
a: micrometastasis
b: macrometastasis
c: In transit metastases/satellites without metastatic nodes
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| N3 |
4 or more metastatic nodes, or matted nodes, or in-transit metastases/satellites and metastatic nodes |
| M Classification |
Site |
Serum LDH |
| M0 |
No evidence of metastasis to distant tissues or organs |
| M1a |
Distant skin, subcutaneous or nodal metastases |
Normal |
| M1b |
Lung metastases |
Normal |
| M1c |
All other visceral metastases
Or any distant metastases
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Normal
Elevated
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Abbreviations: N/A, not applicable; LDH, lactate dehydrogenases
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