NCCN Guidelines for Patients® | Colon Cancer - page 16

NCCN Guidelines for Patients
®
Colon Cancer, Version 1.2014
14
2
Cancer staging
Colon cancer stages
T scores for colon cancer include:
Tis
tumors have not grown beyond the first
layer of the colon wall (mucosa).
T1
tumors have grown into the second layer of
the colon wall (submucosa).
T2
tumors have grown into the third layer of
the colon wall (muscularis propria).
T3
tumors have grown into the fourth layer of
the colon wall (serosa or adventitia).
T4a
tumors have grown through the serosa
(also called visceral peritoneum).
T4b
tumors have grown next to or into nearby
organs or structures.
N = Nodes
The N score reflects how far the cancer has spread
within nearby lymph nodes. Nearby lymph nodes
include nodes right outside the colon wall and nodes
along the major arteries that supply blood to the
colon. The N category also reflects the presence of
tumor deposits. Tumor deposits are small secondary
tumors near but separate from the primary tumor. N
scores for colon cancer include:
N0
means there is no cancer in nearby lymph
nodes.
N1
means the cancer has spread to 1 to 3
nearby lymph nodes.
N1a
means the cancer has spread to 1
nearby lymph node.
N1b
means the cancer as spread to 2 to 3
nearby lymph nodes.
N1c
means there is no cancer in the lymph
nodes but there are tumor deposits within
the fat that is inside or right outside the
colon wall.
N2
means the cancer has spread to 4 or more
nearby lymph nodes.
N2a
means the cancer has spread to 4 to 6
nearby lymph nodes.
N2b
means the cancer as spread to 7 or
more nearby lymph nodes.
M = Metastasis
The M category tells you if the cancer has spread to
distant sites. Distant sites include the liver, lungs, or
distant lymph nodes. Colon cancer can also spread to
the parietal peritoneum, which is a thin layer of tissue
that covers the abdominal wall. M scores for colon
cancer include:
M0
means the cancer hasn’t spread to distant
sites.
M1
means the cancer has spread to distant
sites.
M1a
cancer has spread to one distant site.
M1b
cancer has spread to two or more
distant sites or to the parietal peritoneum.
Colon cancer stages
Chart 2.1
shows the staging groups labeled by
Roman numerals 0 to IV. The stages are defined
by the TNM scores. Dukes and MAC are two other
definitions used for staging, but these definitions are
not often used.
Cancer is often staged twice. The first rating is done
before treatment and is called the clinical stage.
The second rating is done after treatment, such as
surgery, and is called the pathologic stage.
In general, earlier cancer stages have better
outcomes. However, doctors define cancer stages
with information from thousands of patients, so a
cancer stage gives an average outcome. It may not
tell the outcome for one person. Some people will
do better than expected. Others will do worse. Other
factors not used for staging cancer, such as your
general health, are also very important.
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