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The stage describes the extent of the cancer in the body. It
is based on whether the cancer is invasive or non-invasive, the size of
the tumor, how many lymph nodes are involved, and if it has spread to
other parts of the body. The stage of a cancer is one of the most
important factors in determining prognosis and treatment options.
Staging is the process of finding out how widespread a cancer
is when it is diagnosed. Depending on the results of your physical exam
and biopsy, your doctor may want you to have certain imaging tests such
as a chest x-ray, mammograms of both breasts, bone scans, computed
tomography (CT) scans, magnetic resonance imaging (MRI), and/or
positron emission tomography (PET) scans (see below). Blood tests may
also be done to evaluate your overall health and help find out if the
cancer has spread to certain organs.
Imaging tests that look for breast cancer
spread
Once breast cancer is diagnosed, one or more of the following
tests may be done.
Chest x-ray
This test may be done to see whether the breast cancer has
spread to your lungs.
Mammogram
If they haven't been done already, more extensive mammograms
may be done to get more thorough views of the breasts. This is to check
for any other abnormal areas that could be cancer as well. This test is
described in the section "How
is breast cancer diagnosed?"
Bone scan
A bone scan can help show whether a cancer has spread
(metastasized) to your bones. It can be more useful than standard
x-rays because it can show all of the bones of the body at the same
time.
For this test, a small amount of low-level radioactive
material is injected into a vein (intravenously, or IV). The substance
settles in areas of bone changes throughout the entire skeleton over
the course of a couple of hours. You then lie on a table for about 30
minutes while a special camera detects the radioactivity and creates a
picture of your skeleton.
Areas of bone changes appear as "hot spots" on your skeleton
-- that is, they attract the radioactivity. These areas may suggest the
presence of metastatic cancer, but arthritis or other bone diseases can
also cause the same pattern. To distinguish between these conditions,
your cancer care team may use other imaging tests such as simple x-rays
or CT or MRI scans to get a better look at the areas that light up, or
they may even take biopsy samples of the bone.
Computed tomography (CT) scan
The CT scan is an x-ray test that produces detailed
cross-sectional images of your body. Instead of taking one picture,
like a regular x-ray, a CT scanner takes many pictures as it rotates
around you while you lie on a table. A computer then combines these
pictures into images of slices of the part of your body being studied.
In women with breast cancer, this test is most often used to look at
the chest and/or abdomen to see if the cancer has spread to other
organs.
Before any pictures are taken, you may be asked to drink 1 to
2 pints of a liquid called oral
contrast. This helps outline the intestine so that certain
areas are not mistaken for tumors. You may also receive an IV
(intravenous) line through which a different kind of contrast dye (IV
contrast) is injected. This helps better outline structures in your
body.
The injection might cause some flushing (a feeling of warmth,
especially in the face). Some people are allergic and get hives.
Rarely, more serious reactions like trouble breathing or low blood
pressure can occur. Medicine can be given to prevent and treat allergic
reactions. Be sure to tell the doctor if you have ever had a reaction
to any contrast material used for x-rays.
CT scans take longer than regular x-rays. You need to lie
still on a table while they are being done. During the test, the table
moves in and out of the scanner, a ring-shaped machine that completely
surrounds the table. You might feel a bit confined by the ring you have
to lie in while the pictures are being taken.
CT guided needle
biopsy: CT scans can also be used to precisely guide a
biopsy needle into a suspected area of cancer spread. For this
procedure, you remain on the CT scanning table while a radiologist
advances a biopsy needle through the skin and toward the location of
the mass. CT scans are repeated until the doctors are sure that the
needle is within the mass. A fine needle biopsy sample (tiny fragment
of tissue) or a core needle biopsy sample (a thin cylinder of tissue
about ½-inch long and less than 1/8-inch in diameter) is
then removed and sent to be looked at under a microscope.
Magnetic resonance imaging (MRI) scan
This test is described in the sections "Can
breast cancer be found early?" and "How
is breast cancer diagnosed?" as an imaging test of the
breast. It may be used to examine the breast with cancer, to look for
other tumors. It may also be used to look at the opposite breast, to be
sure that it does not contain any tumors. It is not yet clear how
helpful this is in planning surgery in someone known to have breast
cancer.
MRI scans are also used to look for cancer that has spread to
various parts of the body, just like CT scans. MRI scans are
particularly helpful in looking at the brain and spinal cord.
MRI scans use radio waves and very strong magnets instead of
x-rays. The energy from the radio waves is absorbed and then released
in a pattern formed by the type of body tissue and by certain diseases.
A computer translates the pattern into a very detailed image of parts
of the body. A contrast material called gadolinium is often
injected into a vein before the scan to better see details.
MRI scans are a little more uncomfortable than CT scans.
First, they take longer -- often up to an hour. Second, you have to lie
inside a narrow tube, which is confining and can upset people with
claustrophobia (a fear of enclosed spaces). Newer, "open" MRI machines
can sometimes help with this if needed. The machine also makes buzzing
and clicking noises that you may find disturbing. Some centers provide
headphones with music to block this noise out.
Ultrasound
This test is described in the section "How
is breast cancer diagnosed?" as an imaging test of the
breast. But ultrasound can also be used to look for cancer that has
spread to some other parts of the body.
Ultrasound tests use sound waves and their echoes to produce a
picture of internal organs or masses. A small microphone-like
instrument called a transducer
sends out sound waves and picks up the echoes as they bounce off body
tissues. The echoes are converted by a computer into a black and white
image that is shown on a computer screen. This test is painless and
does not expose you to radiation.
Abdominal ultrasound can be used to look for tumors in your
liver or other abdominal organs. When you have an abdominal ultrasound
exam, you simply lie on a table and a technician moves the transducer
over the skin overlying the part of your body being examined. Usually,
the skin is first lubricated with gel.
Positron emission tomography (PET) scan
For a PET scan, glucose (a form of sugar) that contains a
radioactive atom is injected into the bloodstream. Because cancer cells
in the body are growing rapidly, they absorb large amounts of the
radioactive sugar. After about an hour, a special camera is used to
create a picture of areas of radioactivity in the body.
A PET scan is useful when your doctor thinks the cancer may
have spread but doesn't know where. The picture is not finely detailed
like a CT or MRI scan, but it provides helpful information about your
whole body. Some newer machines are able to do both a PET and CT scan
at the same time (PET/CT scan). This allows the radiologist to compare
areas of higher radioactivity on the PET with the appearance of that
area on the CT.
So far, most studies show it isn't very helpful in most cases
of breast cancer, although it may be used when the cancer is known to
have spread.
The American Joint Committee on Cancer
(AJCC) TNM system
A staging system is a standardized way for the cancer care
team to summarize information about how far a cancer has spread. The
most common system used to describe the stages of breast cancer is the
American Joint Committee on Cancer (AJCC) TNM system.
The stage of a breast cancer can be based either on the
results of physical exam, biopsy, and imaging tests (called the clinical stage), or
on the results of these tests plus the results of surgery (called the pathologic stage).
The staging described here is the pathologic stage, which includes the
findings after surgery, when the pathologist has looked at the breast
mass and nearby lymph nodes. Pathologic staging is likely to be more
accurate than clinical staging, as it allows the doctor to get a
firsthand impression of the extent of the cancer.
The TNM staging system classifies cancers based on their T, N,
and M stages:
- T
stands for tumor
(its size and how far it has spread within the breast and to nearby
organs).
- N
stands for spread to lymph nodes
(bean-shaped collections of immune system cells).
- M
is for metastasis
(spread to distant organs).
Additional letters or numbers appear after T, N, and M to give
more details about the tumor, lymph nodes, and metastasis:
- The letter T followed by a number from 0 to 4 describes the
tumor's size and spread to the skin or to the chest wall under the
breast. Higher T numbers mean a larger tumor and/or wider spread to
tissues near the breast.
- The letter N followed by a number from 0 to 3 indicates
whether the cancer has spread to lymph nodes near the breast and, if
so, how many lymph nodes are affected.
- The letter M followed by a 0 or 1 indicates whether the
cancer has spread to distant organs -- for example, the lungs or bones.
Breast cancer T, N, and M categories
Primary tumor (T):
TX: Primary tumor
cannot be assessed.
T0: No
evidence of primary tumor.
Tis:
Carcinoma in situ (DCIS, LCIS, or Paget disease of the nipple with no
associated tumor mass)
T1: Tumor is
2 cm (3/4 of an inch) or less across.
T2: Tumor is
more than 2 cm but not more than 5 cm (2 inches) across.
T3: Tumor is
more than 5 cm across.
T4: Tumor of
any size growing into the chest wall or skin. This includes
inflammatory breast cancer.
Nearby lymph nodes (N) (based on looking at
them under a microscope):
NX: Nearby lymph
nodes cannot be assessed (for example, removed previously).
N0: Cancer
has not spread to nearby lymph nodes.
N1: Cancer
has spread to 1 to 3 axillary (underarm) lymph node(s), and/or tiny
amounts of cancer are found in internal mammary lymph nodes (those near
the breast bone) on sentinel lymph node biopsy.
N2: Cancer
has spread to 4 to 9 lymph nodes under the arm, or cancer has enlarged
the internal mammary lymph nodes.
N3: One of
the following applies:
Cancer has spread to 10 or
more axillary lymph nodes.
Cancer has spread to the lymph nodes under the clavicle (collar bone).
Cancer has spread to the lymph nodes above the clavicle.
Cancer involves axillary lymph nodes and has enlarged the internal
mammary lymph nodes.
Cancer involves 4 or more axillary lymph nodes, and tiny amounts of
cancer are found in internal mammary lymph nodes on sentinel lymph node
biopsy.
Metastasis (M):
MX: Presence of
distant spread (metastasis) cannot be assessed.
M0: No
distant spread.
M1: Spread
to distant organs is present. (The most common sites are bone, lung,
brain, and liver.)
Breast cancer stage grouping
Once the T, N, and M categories have been determined, this
information is combined in a process called stage grouping.
Cancers with similar stages tend to have a similar outlook and thus are
often treated in a similar way. Stage is expressed in Roman numerals
from stage I (the least advanced stage) to stage IV (the most advanced
stage). Non-invasive cancer is listed as stage 0.
Stage 0: Tis,
N0, M0: This is ductal
carcinoma in situ (DCIS), the earliest form of breast
cancer. In DCIS, cancer cells are still within a duct and have not
invaded deeper into the surrounding fatty breast tissue. Lobular carcinoma in situ (LCIS)
is sometimes also classified as stage 0 breast cancer, but most
oncologists believe it is not a true breast cancer. In LCIS, abnormal
cells grow within the lobules or milk-producing glands, but they do not
penetrate through the wall of these lobules. Paget disease of the
nipple (without an underlying tumor mass) is also stage 0. In all cases
the cancer has not spread to lymph nodes or distant sites.
Stage I: T1, N0,
M0: The tumor is 2 cm (about 3/4 of an inch) or less
across and has not spread to lymph nodes or distant sites.
Stage IIA: T0,
N1, M0 / T1, N1, M0 / T2, N0, M0: One of the following
applies:
- The tumor is 2 cm or less across (or is not found) and has
spread to 1 to 3 axillary lymph nodes (T0 or T1, N1).
- The tumor is 2 cm or less across (or is not found) and tiny
amounts of cancer are found in internal mammary lymph nodes on sentinel
lymph node biopsy (T0 or T1, N1).
- The tumor is larger than 2 cm across and less than 5 cm but
hasn't spread to the lymph nodes (T2, N0).
The cancer hasn't spread to distant sites (M0).
Stage IIB: T2,
N1, M0 / T3, N0, M0: One of the following applies:
- The tumor is larger than 2 cm and less than 5 cm across. It
has spread to 1 to 3 axillary lymph nodes and/or tiny amounts of cancer
are found in internal mammary lymph nodes on sentinel lymph node biopsy
(T2, N1).
- The tumor is larger than 5 cm across but does not grow into
the chest wall or skin and has not spread to lymph nodes (T3, N0).
The cancer hasn't spread to distant sites (M0).
Stage IIIA: T0
to T2, N2, M0 / T3, N1, N2, M0: One of the following
applies:
- The tumor is not more than 5 cm across (or cannot be
found). It has spread to 4 to 9 axillary lymph nodes, or it has
enlarged the internal mammary lymph nodes (T0 to T2, N2).
- The tumor is larger than 5 cm across but does not grow into
the chest wall or skin. It has spread to 1 to 9 axillary nodes, or to
internal mammary nodes (T3, N1, or N2).
The cancer hasn't spread to distant sites (M0).
Stage IIIB: T4,
N0 to N2, M0: The tumor has grown into the chest wall or
skin (T4), and one of the following applies:
- It has not spread to the lymph nodes (N0).
- It has spread to 1 to 3 axillary lymph nodes and/or tiny
amounts of cancer are found in internal mammary lymph nodes on sentinel
lymph node biopsy (N1).
- It has spread to 4 to 9 axillary lymph nodes, or it has
enlarged the internal mammary lymph nodes (N2).
The cancer hasn't spread to distant sites (M0).
Inflammatory breast cancer is classified as T4 and is stage
IIIB unless it has spread to distant lymph nodes or organs, in which
case it would be stage IV.
Stage IIIC: any
T, N3, M0: The tumor is any size (or can't be found), and
one of the following applies:
- Cancer has spread to 10 or more axillary lymph nodes (N3).
- Cancer has spread to the lymph nodes under the clavicle
(collar bone) (N3).
- Cancer has spread to the lymph nodes above the clavicle
(N3).
- Cancer involves axillary lymph nodes and has enlarged the
internal mammary lymph nodes (N3).
- Cancer has spread to 4 or more axillary lymph nodes, and
tiny amounts of cancer are found in internal mammary lymph nodes on
sentinel lymph node biopsy (N3).
The cancer hasn't spread to distant sites (M0).
Stage IV: any T,
any N, M1: The cancer can be any size (any T) and may or
may not have spread to nearby lymph nodes (any N). It has spread to
distant organs or to lymph nodes far from the breast (M1). The most
common sites of spread are the bone, liver, brain, or lung,.
If you have any questions about the stage of your cancer and
what it might mean in your case, be sure to ask your doctor.
Breast cancer survival rates by stage
The numbers below come from the National Cancer Institute's
Surveillance, Epidemiology, and End Results (SEER) database, and are
based on women who were diagnosed with breast cancer between 1988 and
2001. There are some important points to note about these numbers:
- The 5-year
survival rate refers to the percentage of patients who
live at least 5 years
after being diagnosed with cancer. Many of these patients live much
longer than 5 years after diagnosis. Five-year relative survival
rates (such as the numbers below) take into account the fact that some
patients with cancer will die from other causes. They are considered to
be a more accurate way to describe the outlook for patients with a
particular type and stage of cancer.
- The SEER database does not divide survival rates by
substages, such as IIA and IIB. The rates for these substages are
likely to be close to the rate for the overall stage. For example, the
survival rate for stage IIA is likely to be slightly higher than that
listed for stage II, while the survival rate for stage IIB would be
expected to be slightly lower.
- These numbers were taken from patients treated several
years ago. Although they are among the most current numbers we have
available, improvements in treatment since then mean that the survival
rates for people now being diagnosed with these cancers may be higher.
- While survival statistics can sometimes be useful as a
general guide, they may not accurately represent any one person's
prognosis. A number of other factors, including other tumor
characteristics and a person's age and general health, can also affect
outlook. Your doctor can tell you how these numbers may apply to you,
as he or she is familiar with the aspects of your particular situation.
| Stage |
5-year
Relative Survival Rate |
| 0 |
100% |
| I |
100% |
| II |
86% |
| III |
57% |
| IV |
20% |
Last Medical Review: 09/18/2009 Last Revised: 09/18/2009
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