Women are recommended to undergo regular breast exams and mammograms to detect breast cancer early on. Breast cancer treatment is likely to be much more successful if the cancer is detected early.

Breast cancer testing

In a clinical breast exam, a doctor will check a woman’s breasts. A woman may be asked to raise her arms over her head, hang her arms by her sides, and put her hands on her hips as part of the testing process. A doctor will examine the breasts for differences in size or shape. The skin of the breasts will also be checked for dimpling, rashes, or other abnormalities. A doctor may squeeze the nipples to check for fluid discharge. A doctor will manually check the breasts, underarms, and collarbone area for any abnormalities. However, a breast lump has to grow to the size of a pea before it can be felt. A doctor will also check the lymph nodes located near the breasts to see if they have become enlarged.

If a lump is detected, a doctor will examine its shape, size, and texture. A doctor will also check to see if a lump moves easily since a benign lump will normally feel much different from a cancerous lump. A breast lump that is smooth, round, soft, and malleable is probably benign. A hard, uneven shaped lump firmly attached to breast tissue is more likely to be cancerous but will require further testing.

After the initial exam, a mammogram will be used to take an x-ray of the breast tissue. Mammograms will often reveal a breast lump before it is large enough to be felt by hand.

Other forms of testing for breast cancer may include:

• Breast MRI
• Breast ultrasound
• Breast biopsy
• CT scan
• PET scan
• Sentinel lymph node biopsy

Breast cancer staging

If breast cancer is detected, more testing will be necessary to see if and where cancer has spread. This type of testing is used to determine the stage of breast cancer to prescribe further treatment.

 

The American Joint Committee on Cancer 

A staging system is a standardized way for the cancer care team to summarize information about how far 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 breast cancer can be based either on the results of a 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 cancer.

The TNM staging system classifies cancers based on their T, N, and M stages:

• 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 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 cancer has spread to distant organs -- for example, the lungs or bones.

Here are the various stages of breast cancer:

 

Primary tumor (T) categories:

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 (includes T1a, T1b, and T1c): 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.

NX: Nearby lymph nodes cannot be assessed (for example, if they were removed previously).

N0: Cancer has not spread to nearby lymph nodes.

• N0(i+): Tiny amounts of cancer are found in underarm lymph nodes by using either routine or special stains. The area of cancer spread contains less than 200 cells and is smaller than 0.2 mm.
• N0(mol+): Cancer cells cannot be seen in underarm lymph nodes (even using special stains), but traces of cancer cells were detected using RT-PCR.

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.

• N1mi: Micrometastases (tiny areas of cancer spread) in 1 to 3 lymph nodes under the arm. The areas of cancer spread in the lymph nodes are 2 mm or less across (but at least 200 cancer cells or 0.2mm across).
• N1a: Cancer has spread to 1 to 3 lymph nodes under the arm with at least one area of cancer spread greater than 2 mm across.
• N1b: Cancer has spread to internal mammary lymph nodes, but this spread could only be found on sentinel lymph node biopsy (it did not cause the lymph nodes to become enlarged).
• N1c: Both N1a and N1b apply.

N2: Cancer has spread to 4 to 9 lymph nodes under the arm, or cancer has enlarged the internal mammary lymph nodes (either N2a or N2b, but not both).

• N2a: Cancer has spread to 4 to 9 lymph nodes under the arm, with at least one area of cancer spread larger than 2 mm.
• N2b: Cancer has spread to one or more internal mammary lymph nodes, causing them to become enlarged.

N3: Any of the following:

N3a: either

• Cancer has spread to 10 or more axillary lymph nodes, with at least one area of cancer spread greater than 2mm, OR
• Cancer has spread to the lymph nodes under the clavicle (collar bone), with at least one area of cancer spread greater than 2mm.

N3b: either:

• Cancer is found in at least one axillary lymph node (with at least one area of cancer spread greater than 2 mm) and has enlarged the internal mammary lymph nodes, OR
• Cancer involves 4 or more axillary lymph nodes (with at least one area of cancer spread greater than 2 mm), and tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy.
• N3c: Cancer has spread to the lymph nodes above the clavicle with at least one area of cancer spread greater than 2mm.

Metastasis (M):

MX: The 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. The 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 true breast cancer. Paget disease of the nipple (without an underlying tumor mass) is also stage 0. In all cases, 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 (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). 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 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).

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). 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). 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). 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). 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).

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).

Cancer hasn't spread to distant sites (M0).

Stage IV: any T, any N, M1: 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,

 

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