Key Points for This Section

After breast cancer has been diagnosed, tests are done to find out if cancer cells have spread within the breast or to other parts of the body. There are three ways that cancer spreads in the body. The following stages are used for breast cancer: Stage 0 (carcinoma in situ) Stage I Stage IIA Stage IIB Stage IIIA Stage IIIB Stage IIIC Stage IV

After breast cancer has been diagnosed, tests are done to find out if cancer cells have spread within the breast or to other parts of the body.

The process used to find out whether the cancer has spread within the breast or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

• Through tissue. Cancer invades the surrounding normal tissue.
• Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
• Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for breast cancer:

Stage 0 (carcinoma in situ)

There are 2 types of breast carcinoma in situ:

• Ductal carcinoma in situ (DCIS) is a noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, DCIS may become invasive cancer and spread to other tissues, although it is not known at this time how to predict which lesions will become invasive.
• Lobular carcinoma in situ (LCIS) is a condition in which abnormal cells are found in the lobules of the breast. This condition seldom becomes invasive cancer; however, having lobular carcinoma in situ in one breast increases the risk of developing breast cancer in either breast.

Enlarge

Pea, peanut, walnut, and lime show tumor sizes.

Stage I

In stage I, cancer has formed. The tumor is 2 centimeters or smaller and has not spread outside the breast.

Stage IIA

In stage IIA:

• no tumor is found in the breast, but cancer is found in the axillary lymph nodes (the lymph nodes under the arm); or
• the tumor is 2 centimeters or smaller and has spread to the axillary lymph nodes; or
• the tumor is larger than 2 centimeters but not larger than 5 centimeters and has not spread to the axillary lymph nodes.

Stage IIB

In stage IIB, the tumor is either:

• larger than 2 centimeters but not larger than 5 centimeters and has spread to the axillary lymph nodes; or
• larger than 5 centimeters but has not spread to the axillary lymph nodes.

Stage IIIA

In stage IIIA:

• no tumor is found in the breast. Cancer is found in axillary lymph nodes that are attached to each other or to other structures, or cancer may be found in lymph nodes near the breastbone; or
• the tumor is 2 centimeters or smaller. Cancer has spread to axillary lymph nodes that are attached to each other or to other structures, or cancer may have spread to lymph nodes near the breastbone; or
• the tumor is larger than 2 centimeters but not larger than 5 centimeters. Cancer has spread to axillary lymph nodes that are attached to each other or to other structures, or cancer may have spread to lymph nodes near the breastbone; or
• the tumor is larger than 5 centimeters. Cancer has spread to axillary lymph nodes that may be attached to each other or to other structures, or cancer may have spread to lymph nodes near the breastbone.

Stage IIIB

In stage IIIB, the tumor may be any size and cancer:

• has spread to the chest wall and/or the skin of the breast; and
• may have spread to axillary lymph nodes that may be attached to each other or to other structures, or cancer may have spread to lymph nodes near the breastbone.

Cancer that has spread to the skin of the breast is inflammatory breast cancer. See the section on Inflammatory Breast Cancer ¹ for more information.

Stage IIIC

In stage IIIC, there may be no sign of cancer in the breast or the tumor may be any size and may have spread to the chest wall and/or the skin of the breast. Also, cancer:

• has spread to lymph nodes above or below the collarbone; and
• may have spread to axillary lymph nodes or to lymph nodes near the breastbone.

Cancer that has spread to the skin of the breast is inflammatory breast cancer. See the section on Inflammatory Breast Cancer ¹ for more information.

Stage IIIC breast cancer is divided into operable and inoperable stage IIIC.

In operable stage IIIC, the cancer:

• is found in ten or more axillary lymph nodes; or
• is found in lymph nodes below the collarbone; or
• is found in axillary lymph nodes and in lymph nodes near the breastbone.

In inoperable stage IIIC breast cancer, the cancer has spread to the lymph nodes above the collarbone.

Stage IV

In stage IV, the cancer has spread to other organs of the body, most often the bones, lungs, liver, or brain.

Glossary Terms

Not normal. An abnormal lesion or growth may be cancer, premalignant (likely to become cancer), or benign (not cancer).

A lymph node in the armpit region that drains lymph channels from the breast.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

Primary bone cancer is cancer that forms in cells of the bone. Some types of primary bone cancer are osteosarcoma, Ewing sarcoma, malignant fibrous histiocytoma, and chondrosarcoma. Secondary bone cancer is cancer that spreads to the bone from another part of the body (such as the prostate, breast, or lung).

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

There are 2 types of breast carcinoma in situ: ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). DCIS is a noninvasive condition in which abnormal cells are found in the lining of a breast duct (a tube that carries milk to the nipple). The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, DCIS may spread to other tissues, although it is not known how to predict which lesions will become invasive cancer. LCIS is a condition in which abnormal cells are found in the lobules (small sections of tissue involved with making milk) of the breast. This condition seldom becomes invasive cancer; however, having LCIS in one breast increases the risk of developing breast cancer in either breast. Also called stage 0 breast carcinoma in situ.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The smallest type of blood vessel. A capillary connects an arteriole (small artery) to a venule (small vein) to form a network of blood vessels in almost all parts of the body. The wall of a capillary is thin and leaky, and capillaries are involved in the exchange of fluids and gases between tissues and the blood.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A measure of length in the metric system. There are 100 centimeters in a meter and 2½ centimeters in an inch.

The muscles, bones, and joints that make up the area of the body between the neck and the abdomen.

In medicine, a tube or vessel of the body through which fluids pass.

A noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, ductal carcinoma in situ may become invasive cancer and spread to other tissues, although it is not known at this time how to predict which lesions will become invasive. Also called DCIS and intraductal carcinoma.

A type of breast cancer in which the breast looks red and swollen and feels warm. The skin of the breast may also show the pitted appearance called peau d'orange (like the skin of an orange). The redness and warmth occur because the cancer cells block the lymph vessels in the skin.

Describes a condition that cannot be treated by surgery.

Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.

An area of abnormal tissue. A lesion may be benign (not cancer) or malignant (cancer).

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

A condition in which abnormal cells are found in the lobules of the breast. Lobular carcinoma in situ seldom becomes invasive cancer; however, having it in one breast increases the risk of developing breast cancer in either breast. Also called LCIS.

A small lobe or a subdivision of a lobe.

One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.

The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.

The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).

In medicine, it describes a procedure that does not require inserting an instrument through the skin or into a body opening. In cancer, it describes disease that has not spread outside the tissue in which it began.

Describes a condition that can be treated by surgery.

A part of the body that performs a specific function. For example, the heart is an organ.

The original tumor.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

The tumor is 2 centimeters or smaller and has not spread outside the breast.

Stage II is divided into stages IIA and IIB. In stage IIA, (1) no tumor is found in the breast, but cancer is found in the axillary lymph nodes (the lymph nodes under the arm); or (2) the tumor is 2 centimeters or smaller and has spread to the axillary lymph nodes; or (3) the tumor is larger than 2 centimeters but not larger than 5 centimeters and has not spread to the axillary lymph nodes. In stage IIB, the tumor is either (1) larger than 2 centimeters but not larger than 5 centimeters and has spread to the axillary lymph nodes; or (2) larger than 5 centimeters but has not spread to the axillary lymph nodes.

Stage III breast cancer is divided into stages IIIA, IIIB, and IIIC. In stage IIIA, (1) no tumor is found in the breast, but cancer is found in axillary (under the arm) lymph nodes that are attached to each other or to other structures, or cancer may be found in lymph nodes near the breastbone; or (2) the tumor is 2 centimeters or smaller and cancer has spread to axillary lymph nodes that are attached to each other or to other structures, or the cancer may have spread to lymph nodes near the breastbone; or (3) the tumor is larger than 2 centimeters but not larger than 5 centimeters and cancer has spread to axillary lymph nodes that are attached to each other or to other structures or cancer may have spread to lymph nodes near the breastbone; or (4) the tumor is larger than 5 centimeters and cancer has spread to axillary lymph nodes that may be attached to each other or to other structures or the cancer may have spread to lymph nodes near the breastbone.

Stage III breast cancer is divided into stages IIIA, IIIB, and IIIC. In stage IIIB, the tumor may be any size and cancer (1) has spread to the chest wall and/or the skin of the breast; and (2) may have spread to axillary lymph nodes that may be attached to each other or to other structures or the cancer may have spread to lymph nodes near the breastbone.

Stage III breast cancer is divided into stages IIIA, IIIB, and IIIC. In stage IIIC, no tumor is found in the breast or the tumor may be any size and may have spread to the chest wall and/or the skin of the breast. Cancer has spread to lymph nodes above or below the collarbone and may have spread to axillary lymph nodes or to lymph nodes near the breastbone. In operable stage IIIC, the cancer (1) is found in ten or more axillary lymph nodes; or (2) is found in the lymph nodes below the collarbone; or (3) is found in axillary lymph nodes and in lymph nodes near the breastbone. In inoperable stage IIIC, the cancer has spread to the lymph nodes above the collarbone.

Cancer has spread to other organs of the body, most often the bones, lungs, liver, or brain.

Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body. It is important to know the stage of the disease in order to plan the best treatment.

A group or layer of cells that work together to perform a specific function.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

A blood vessel that carries blood to the heart from tissues and organs in the body.