Metastasis (M):

Metastasis (M):

MX: Presence of distant spread (metastasis) cannot be assessed.
M0: No distant spread is found on x-rays (or other imaging procedures) or by physical
exam.
· cM0(i +): Small numbers of cancer cells are found in blood or bone marrow (found
only by special tests), or tiny areas of cancer spread (no larger than 0.2 mm) are found
in lymph nodes away from the breast.
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. 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 IA: T1, N0, M0: The tumor is 2 cm (about 3/4 of an inch) or less across (T1) and
has not spread to lymph nodes (N0) or distant sites (M0).
Stage IB: T0 or T1, N1mi, M0: The tumor is 2 cm or less across (or is not found) (T0 or
T1) with micrometastases in 1 to 3 axillary lymph nodes (the cancer in the lymph nodes
is greater than 0.2mm across and/or more than 200 cells but is not larger than 2
mm)(N1mi). The cancer has not spread to distant sites (M0).
Stage IIA: One of the following applies:
T0 or T1, N1 (but not N1mi), M0: The tumor is 2 cm or less across (or is not found) (T1
or T0) and either:
· It has spread to 1 to 3 axillary lymph nodes, with the cancer in the lymph nodes larger
than 2 mm across (N1a), OR
· Tiny amounts of cancer are found in internal mammary lymph nodes on sentinel
lymph node biopsy (N1b), OR
· It has spread to 1 to 3 lymph nodes under the arm and to internal mammary lymph
nodes (found on sentinel lymph node biopsy) (N1c).

OR
T2, N0, M0: The tumor is larger than 2 cm across and less than 5 cm (T2) but hasn't
spread to the lymph nodes (N0).
The cancer hasn't spread to distant sites (M0).
Stage IIB: One of the following applies:
T2, N1, M0: The tumor is larger than 2 cm and less than 5 cm across (T2). 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). The cancer hasn't spread to
distant sites (M0).
OR
T3, N0, M0: 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: One of the following applies:
T0 to T2, N2, M0: The tumor is not more than 5 cm across (or cannot be found) (T0 to
T2). 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).
OR
T3, N1 or N2, M0: The tumor is larger than 5 cm across but does not grow into the chest
wall or skin (T3). It has spread to 1 to 9 axillary nodes, or to internal mammary nodes
(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 at least stage IIIB. If it has spread to
many nearby lymph nodes (N3) it could be stage IIIC, and if it has spread to distant
lymph nodes or organs (M1) 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.