NCCN Guidelines for Patients
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Part 3: Melanoma staging
groups of special disease-
fighting cells located
throughout the body
mass of cancer cells in the
See Part 2 on page
16 for test details
3.1 What is staging?
Cancer staging is a way to rate and describe the extent of cancer in the body.
It’s used for treatment planning. Cancer stages are defined by the growth of
the primary tumor and its spread to other sites in the body. There are five main
stages of melanoma based mainly on tumor depth, how many lymph nodes are
involved, and how far the cancer has spread.
3.2 TNM scores
The TNM staging system is used to stage melanoma skin cancer. In this system,
each of the letters—T, N, and M—describes a different area of cancer growth.
Your doctor will assign a score to each letter. TNM scores are based on the
tests described in Part 2. These scores are used to assign the cancer a stage.
T = Tumor
The T category tells you how thick the primary tumor is (Figure 9). The T
category is given a score from 1 to 4 based on how deep the tumor has grown
into the skin, measured in mm (
eters). The sharp point of a pencil is
about 1 mm. For T1 to T4 melanomas, subcategories are given based on
two important factors. The first factor is the ulceration status—whether or not
the tumor’s top skin layer is present and intact (not ulcerated) or is broken or
missing (ulcerated). The second factor is the dermal mitotic rate—a measure of
how many tumor cells are dividing per mm
eter squared) of melanoma