Oncologist-approved cancer information from the American Society of Clinical Oncology
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Breast Cancer - Metaplastic

This section has been reviewed and approved by the Cancer.Net Editorial Board, 8/2010
Stages

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 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. There are different stage descriptions for different types of cancer.

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 size of the tumor itself, the presence of cancer in the lymph nodes around the tumor, and whether 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), which is non-invasive ductal carcinoma in situ (DCIS), and stages I through IV (one through four), which represent invasive breast cancer. 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 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 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 evidence of cancer in the breast.

Tis: Refers to carcinoma (cancer) in situ. In this case, the cancer is confined within the natural boundaries of the breast tissue and has not spread into the surrounding tissue of the breast. There are three types of breast carcinoma in situ:

Tis (DCIS): Ductal carcinoma in situ (DCIS) is a precancer, but it can later develop into an invasive type of breast cancer. A designation of DCIS means that only a few cancer cells have been found in breast ducts and have not spread past the layer of tissue where they began.

Tis (LCIS): Lobular carcinoma in situ (LCIS) describes abnormal cells found in the lobules or glands of the breast. LCIS is not cancer, but it increases the risk of developing invasive breast cancer.

Tis (Paget's): Paget's disease of the nipple is a rare form of early breast cancer. This designation is used only if there is Paget's disease but no tumor present. If there is a tumor, it is classified according to the size of the tumor.

T1: A tumor in the breast is 2 centimeters (cm) or smaller in size at its widest dimension.

T1mic: Microinvasion, or micrometastases, means a few cancer cells have spread to surrounding tissue, but none larger than 0.1 cm.

T1a: The tumor is larger than 0.1 cm but smaller than 0.5 cm.

T1b: The tumor is larger than 0.5 cm but smaller than 1 cm.

T1c: The tumor is larger than 1 cm but not larger than 2 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 spread to the chest wall or to the skin or is diagnosed as inflammatory breast cancer.

T4a: The tumor has spread into the chest wall.

T4b: There is edema (swelling), thickening of the skin (as in peau d'orange), or ulceration (a sore, painful area where the breast skin/tissue is breaking down) of the breast skin or surrounding skin nodules of the same breast.

T4c: There are signs of both T4a and T4b.

T4d: Refers to inflammatory carcinoma. This is an aggressive type of breast cancer where the breast is red, swollen, and warm.

Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes located under the arm, above and below the collarbone, and under the breastbone are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.

NX: The lymph nodes cannot be evaluated.

N0: No cancer was found in the lymph nodes.

N1: The cancer has spread to one to three axillary lymph nodes.

N2: The cancer has spread to four to nine lymph nodes under the arm or to the internal mammary lymph nodes (lymph nodes to the right or left of the sternum [breastbone] on the inside of the chest) without axillary node involvement.

N2a: The cancer has spread to four to nine lymph nodes under the arm (at least one tumor deposit is larger than 2 mm).

N2b: The cancer has spread only to the internal mammary lymph nodes.

N3: The cancer has spread to 10 or more lymph nodes under the arm or to the infraclavicular lymph nodes (located under the collarbone) or to the internal mammary nodes with axillary node involvement.

N3a: The cancer has spread to 10 or more lymph nodes under the arm or to the infraclavicular lymph nodes.

N3b: The cancer has spread to internal mammary nodes and axillary nodes.

N3c: The cancer has spread to the supraclavicular lymph nodes.

If there is cancer in the lymph nodes, it also helps doctors to plan treatment to know how many lymph nodes are involved. The pathologist can determine the number of lymph nodes affected by cancer.

Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread to other parts of the body.

MX: Distant spread cannot be evaluated.

M0: The disease has not metastasized.

M1: There is metastasis to another part of the body.

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications.

Stage 0: Stage zero (0) describes disease that is confined within the ducts and lobules of the breast tissue and has not spread into the surrounding tissue of the breast. It is also called noninvasive cancer (Tis, N0, M0).

Stage IA: The tumor is small, invasive, and has not spread to the lymph nodes (T1, N0, M0).

Stage IB: The tumor is confined within the ducts and lobules of the breast tissue and has not spread into the surrounding tissue of the breast, or it is smaller than 20 mm, with microscopic spread to the lymph nodes (T0 or T1, N1mic, M0).

Stage IIA: Any one of these conditions:

  • There is no evidence of a tumor in the breast, but the cancer has spread to the axillary lymph nodes but not to distant areas of the body. (T0, N1, M0).
  • The tumor is 20 mm or smaller and has spread to the axillary lymph nodes (T1, N1, M0).
  • The tumor is larger than 20 mm but not larger than 50 mm and has not spread to the axillary lymph nodes (T2, N0, M0).

Stage IIB: Any one of these conditions:

  • The tumor is larger than 20 mm but not larger than 50 mm and has spread to one to three axillary lymph nodes (T2, N1, M0).
  • The tumor is larger than 50 mm but has not spread to the axillary lymph nodes (T3, N0, M0).

Stage IIIA: This stage describes a cancer of any size that has spread to four to nine axillary lymph nodes, but not to other parts of the body (T0, T1, T2 or T3, N2, M0). Stage IIIA may also be a tumor larger than 50 mm that has spread to one to three lymph nodes (T3, N1 or N2, M0).

Stage IIIb: The tumor has spread to the chest wall or caused swelling or ulceration of the breast or is diagnosed as inflammatory breast cancer. It may or may not have spread to the lymph nodes under the arm, but has not spread to other parts of the body (T4, N0, M0; T4, N1, M0; or T4, N2, M0).

Stage IIIc: A tumor of any size that has not spread to distant parts of the body but has spread to the lymph nodes in the N3 group (any T, N3, M0).

Stage IV: The tumor can be any size and has spread to distant sites in the body, usually the bones, lungs or liver, or chest wall (any T, any N, M1).

Recurrent: Recurrent cancer is cancer that comes back after treatment.

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual Seventh Edition (2010) published by Springer-Verlag New York, www.cancerstaging.net.

© 2005-2014 American Society of Clinical Oncology (ASCO). All rights reserved worldwide.

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