Ans. :
Staging :
Staging is a way of describing a cancer, such
as where it is located, if or where it has spread,
and if it is affecting the functions of other
organs in the body. Doctors use diagnostic tests
to determine the cancer’s stage, so staging
may not be complete until all of the tests are
finished. Knowing the stage helps the doctor
to decide what kind of treatment is best and
can help predict a patient’s prognosis
(chance of recovery). There are different stage
descriptions for different types of cancers.
One tool that doctors use to describe the stage
is the TNM system. This system uses three criteria
to judge the stage of the cancer: the tumor
itself, the lymph nodes around the tumor, and
if the tumor has spread to other parts of the
body. The results are combined to determine
the stage of cancer for each person. There are
five stages: stage 0 (zero) and stages I through
IV (one through four). The stage provides a
common way of describing the cancer, so doctors
can work together to plan the best treatments.
TNM is an abbreviation for tumor (T), node
(N), and metastasis (M). Doctors look at these
three factors to determine the stage of cancer:
* How large is the
primary tumor and where is it located? (Tumor,
T)
* Has the tumor spread
to the lymph nodes? (Node, N)
* Has the cancer
metastasized (spread) to other parts of the
body? (Metastasis, M)
Tumor :
Using the TNM system, the "T" plus
a letter or number (0 to 4) is used to describe
the size and location of the tumor. Some stages
are also divided into smaller groups that help
describe the tumor in even more detail. Specific
tumor stage information is listed below:
TX: The primary tumor cannot
be evaluated.
T0: There is no tumor.
Tis: Refers to carcinoma in
situ (which is very early cancer that has not
spread.)
T1: The tumor is no larger
than 2 centimeters (cm).
T2: The tumor is larger than
2 cm, but not larger than 5 cm.
T3: The tumor is larger than
5 cm.
T4: The tumor has invaded
other organs, such as the vagina, urethra, or
bladder.
Node :
The “N” in the TNM staging
system stands for lymph nodes, the tiny, bean-shaped
organs that help fight infection. Lymph nodes
near the anus are called regional lymph nodes.
Lymph nodes in other parts of the body are called
distant lymph nodes.
NX: Regional lymph nodes cannot
be evaluated.
N0 (N plus zero): There is
no regional lymph node metastasis.
N1: Cancer had spread to the
perirectal (around the rectum) lymph nodes.
N2: Cancer has spread to the
internal iliac (pelvic) and/or the inguinal
lymph nodes (lymph nodes in the groin just under
the skin surface) on the same side of the body.
N3: Cancer had spread to the
perirectal and inguinal lymph nodes and/or the
internal iliac and/or inguinal lymph nodes on
both sides of the body.
Distant metastasis
: The “M” in the
TNM system indicates whether the cancer has
spread to other parts of the body.
MX: Distant metastasis cannot
be evaluated.
M0 (M plus zero): There is
no distant metastasis.
M1: There is metastasis to
other parts of the body.
Cancer stage
grouping :
Doctors assign the stage of the cancer by combining
the T, N, and M classifications.
Stage 0: Abnormal cells are
in the first layer of the lining of the anus
only. The abnormal cells may become cancer.
This stage is also called carcinoma in situ
(Tis, N0, M0).
Stage I: The tumor is no larger
than 2 cm with no spread to lymph nodes or other
parts of the body (T1, N0, M0).
Stage II: The tumor is larger
than 2 cm with no spread to lymph nodes or other
parts of the body (T2 or T3, N0, M0).
Stage IIIA: The tumor may
be any size and has spread to either nearby
lymph nodes or to organs, such as the vagina,
urethra, and bladder (T1, T2, T3; N1, M0; or
T4, N0, M0).
Stage IIIB: The tumor may
be any size and has spread to nearby lymph nodes
or organs; lymph nodes in the pelvis and/or
groin; or to lymph nodes near the rectum, in
the groin and/or on both sides of the pelvis
or groin (T4, N1, M0; or Any T, N2 or N3, M0).
Stage IV: The tumor may be
any size and has spread to lymph nodes and to
distant parts of the body (Any T, Any N, M1).
Recurrent: Recurrent cancer
is cancer that comes back after treatment.
Grading
Histologic grade (G). In addition
to the TNM system, doctors may also assign a
histologic grade to the cancer. Histologic grade
indicates how closely the cancer cells resemble
normal tissue under a microscope. A tumor's
grade is described using the letter “G”
and a number.
GX: The tumor grade cannot
be identified.
G1: Describes cells that look
more like normal tissue cells (well differentiated).
G2: The cells are somewhat
different from normal cells (moderately differentiated).
G3: The cells do not look
like normal cells (poorly differentiated).
G4: Describes tumor cells
that barely resemble normal cells (undifferentiated).