Breast cancer stages

You learned the stage of your breast cancer, but do you understand what it means? Cancer stages involve myriad measurements and factors, making the process tricky to unravel—but vital. Understanding your stage will help you and your care team make informed treatment decisions, including whether a clinical trial might be best suited for you.

Making an educated treatment decision begins with the stage, or progression, of the disease. Using the results from your diagnostic tests for breast cancer, your care team will develop an appropriate breast cancer treatment plan for you. If you've been recently diagnosed, your doctor will review your pathology to confirm you have received the correct breast cancer diagnosis and staging information, and develop a personalized treatment plan. If you have a recurrence, comprehensive testing will be performed to identify a treatment approach tailored to your needs.

Stages of breast cancer

Staging allows you to answer the following questions:

• How does this cancer typically progress?
• Which treatments may work?

Some of the staging may be even more in-depth, but in general, it’s designed to prepare a more tailored approach to your disease. Your breast cancer stage indicates the severity of the disease upon diagnosis. Your cancer will always retain that label, regardless of its progress.

Breast cancer staging is classified by:

• The size and location of the tumor
• Whether the cancer has spread to nearby lymph nodes or other parts of the body
• The grade of the tumor—or how likely it is to grow and spread
• Whether certain biomarkers—hormone receptors or other proteins—have been found

All these attributes help your care team determine how to treat your cancer.

To assess the location, size and spread of cancer, your care team will use the TNM Staging System, developed and updated for breast cancer by the American Joint Committee on Cancer (AJCC).

• TNM stands for Tumor-Node-Metastasis, which are important factors in determining the severity of your cancer.
• All cancers may be evaluated by TNM markers, but breast cancer staging also uses a few extra criteria for a more detailed description.
• Ultimately, your specific combination of TNM and these other markers will determine your cancer’s stage.

Breast cancer has five general stages under the TNM system: 0 through 4.

What is stage 0 breast cancer?

Also called carcinoma in situ, stage 0 is the earliest breast cancer stage. At stage 0, the breast mass is noninvasive, and there is no indication that the tumor cells have spread to other parts of the breast or other parts of the body. Often, stage 0 is considered a precancerous condition that typically requires close observation, but not treatment.

Stage 0 breast cancer is difficult to detect. There may not be a lump that can be felt during a self-examination, and there may be no other symptoms. However, breast self-exams and routine screening are always important and can often lead to early diagnosis of breast cancer, when the cancer is most treatable. Stage 0 disease is most often found by accident during a breast biopsy for another reason, such as to investigate an unrelated breast lump.

There are two types of stage 0 breast cancer:

Ductal carcinoma in situ (DCIS) occurs when breast cancer cells develop in the breast ducts. Today, stage 0 DCIS is being diagnosed more often because more women are having routine mammogram screenings. DCIS can become invasive, so early treatment can be important.

Lobular carcinoma in situ (LCIS) occurs when abnormal cells develop in the lobules. These cells are not cancerous and this condition rarely becomes invasive cancer. However, women who develop LCIS may be at increased risk for developing breast cancer in the future. For women who develop LCIS, the risk of getting an invasive cancer is 20 percent to 25 percent over 15 years after the initial diagnosis.

What is stage 1 breast cancer?

This breast cancer is the earliest stage of invasive breast cancer. In stage 1, the tumor measures up to 2 cm and no lymph nodes are involved. At this stage, the cancer cells have spread beyond the original location and into the surrounding breast tissue.

Because a stage 1 tumor is small, it may be difficult to detect. However, breast self-exams and routine screening are always important and can often lead to early diagnosis, when the cancer is most treatable. Stage 1 breast cancer is divided into two categories:

Stage 1A: The tumor measures 2 cm or smaller (about the size of a pea or shelled peanut) and has not spread outside the breast.

Stage 1B: Small clusters of cancer cells measuring no more than 2 mm, are found in the lymph nodes, and either there is no tumor inside the breast, or the tumor is small, measuring 2 cm or less.

At stage 1, TNM designations help describe the extent of the disease. For example, there may or may not be cancer cells in the lymph nodes, and the size of the tumor may range from 1 cm to 2 cm. Most commonly, stage 1 breast cancer is described as:

• T: T1, T2, T3 or T4, depending on the size and/or extent of the primary tumor
• N0: Usually, cancer has not spread to the lymph nodes.
• M0: The disease has not spread to other sites in the body.

Stage 1 breast cancer survival rate

The survival rate for stage 1A breast cancer may be slightly higher than for stage 1B. However, all women with stage 1 breast cancer are considered to have a good prognosis.

What is stage 2 breast cancer?

Also known as invasive breast cancer, the tumor in this stage measures between 2 cm to 5 cm, or the cancer has spread to the lymph nodes under the arm on the same side as the breast cancer. Stage 2 breast cancer indicates a slightly more advanced form of the disease. At this stage, the cancer cells have spread beyond the original location and into the surrounding breast tissue, and the tumor is larger than in stage 1 disease. However, stage 2 means the cancer has not spread to a distant part of the body.

At stage 2, a tumor may be detected during a breast self-exam as a hard lump within the breast. Breast self-exams and routine screening are always important and can often lead to early diagnosis, when the cancer is most treatable.

Stage 2 breast cancer is divided into two categories:

Stage 2A: One of the following is true:

• There is no tumor within the breast, but cancer has spread to the axillary (underarm) lymph nodes, or
• The tumor in the breast is 2 cm or smaller and cancer has spread to the axillary lymph nodes, or
• The tumor in the breast measures 2 cm to 5 cm but cancer has not spread to the axillary lymph nodes.

Stage 2B: One of the following is true:

• The tumor measures 2 cm to 5 cm and cancer has spread to the axillary lymph nodes, or
• The tumor is larger than 5 cm but cancer has not spread to the axillary lymph nodes.

At stage 2, TNM designations help describe the extent of the disease. Most commonly, stage 2 breast cancer is described as:

• T: T1, T2, T3 or T4, depending on the size and/or extent of the primary tumor
• N1: Cancer has spread to the lymph nodes.
• M0: The disease has not spread to other sites in the body.

Stage 2 breast cancer survival rate

The survival rate for stage 2A breast cancer may be slightly higher than for stage 2B. However, all women with stage 2 breast cancer are considered to have a good prognosis.

What is stage 3 breast cancer?

Also known as locally advanced breast cancer, the tumor in this stage of breast cancer is more than 2 inches in diameter across and the cancer is extensive in the underarm lymph nodes or has spread to other lymph nodes or tissues near the breast. Stage 3 breast cancer is a more advanced form of invasive breast cancer. At this stage, the cancer cells have usually not spread to more distant sites in the body, but they are present in several axillary (underarm) lymph nodes. The tumor may also be quite large at this stage, possibly extending to the chest wall or the skin of the breast.

Stage 3 breast cancer is divided into three categories:

Stage 3A: One of the following is true:

• No tumor is found in the breast, but cancer is present in axillary lymph nodes that are attached to either other or other structures, or cancer may be found in the lymph nodes near the breast bone, or
• The tumor is 2 cm or smaller. Cancer has spread to axillary lymph nodes that are attached to each other or other structures, or cancer may have spread to lymph nodes near the breastbone, or
• The tumor is 2 cm to 4 cm in size. 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 breast bone, or
• The tumor is larger than 5 cm. 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 3B: The tumor may be any size, and the cancer:

• Has spread to the chest wall and/or 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.

Stage 3C:

• 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 skin of the breast.
• Cancer cells are present in lymph nodes above or below the collarbone.
• Cancer cells may have spread to axillary lymph nodes or lymph nodes near the breastbone.
• Cancer that has spread to the skin of the breast is inflammatory breast cancer.

Stage 3C breast cancer may be operable or inoperable:

• Operable stage 3C: The cancer is found in 10 or more axillary lymph nodes, or is in lymph nodes below the collarbone, or is in axillary lymph nodes and lymph nodes near the breastbone.
• Inoperable stage 3C: The cancer has spread to the lymph nodes above the collarbone.

At stage 3, TNM designations help describe the extent of the disease. Higher numbers indicate more extensive disease. Most commonly, stage 3 breast cancer is described as:

• T: T1, T2, T3 or T4 depends on the size and/or extent of the primary tumor
• N1: Cancer has spread to the lymph nodes.
• M0: The disease has not spread to other sites in the body.

Stage 3 breast cancer survival rate

The survival rate for stage 3A breast cancer may be slightly higher than for stage 3B, and the survival rate for stage 3B may be slightly higher than for stage 3C. However, all women diagnosed with stage 3 breast cancer have several promising treatment options.

What is stage 4 breast cancer?

Also known as metastatic breast cancer, the cancer in this stage has spread beyond the breast, underarm and internal mammary lymph nodes to other parts of the body near to or distant from the breast. The cancer has spread elsewhere in the body. The affected areas may include the bones, brain, lungs or liver and more than one part of the body may be involved.

At stage 4, TNM designations help describe the extent of the disease. Higher numbers indicate more extensive disease. Most commonly, stage 4 breast cancer is described as:,

• T: T1, T2, T3 or T4 depends on the size and/or extent of the primary tumor.
• N1: Cancer has spread to the lymph nodes.
• M1: The disease has spread to other sites in the body.

Recurrent breast cancer

Recurrent breast cancer occurs when the disease has returned after initial treatment. Most recurrent cancers appear within the first two or three years after treatment, but, in some cases, the cancer may recur many years later. According to the Susan G. Komen^® organization, women with early breast cancer most often develop local recurrence within the first five years after treatment. On average, 7 percent to 11 percent of women with early breast cancer experience a local recurrence during this time.

For patients with a family history of cancer, or a BRCA1 or BRCA2 gene mutation, the cancer recurrence rate is higher. The risk of finding new cancers, such as ovarian cancer, may also be higher. Cancer recurrence risk is based on many factors, including the cancer type and how it was treated.

Types of recurrent breast cancer

There are three types of recurrent breast cancer:

Local recurrence is when the cancer has returned to the same location as the original cancer.

Regional recurrence is when the cancer has been found in or near the original location.

Distant recurrence is when the breast cancer has spread to other parts of the body. This is also considered metastatic breast cancer.

It is important to report new signs or symptoms of breast cancer to your doctor. Symptoms of recurrent breast cancer vary from person to person.

Metastatic breast cancer

Metastatic breast cancer, or distant recurrence, occurs when cancer cells have spread to distant organs and/or tissue in the body. Common metastatic areas include the bones, liver and lungs. Even when a metastatic breast tumor spreads to a different part of the body, it contains the same cancerous cells that developed in the breast and is still considered breast cancer.

Signs and symptoms of metastatic breast cancer may include:

• Swelling or lumps in the lymph nodes
• Unexplained pain in other areas of the body, such as the bone
• Difficulty breathing or a persistent cough
• Loss of appetite and/or weight loss
• Intense headaches

Learn more about metastatic breast cancer

Additional markers for breast cancer staging

Additional markers specific to breast cancer will further define your stage, which may be helpful in choosing targeted treatments to fight the cancer.

• ER: The cancer has an estrogen receptor. Estrogen is a hormone, and some cancers have receptors that respond to estrogen.
• PR: The cancer has a progesterone receptor. Progesterone is also a hormone.
• HER2: The cancer makes the protein HER2 (human epidermal growth factor).
• G: Grade of cancer refers to how different the cells look from normal. Grade 1 indicates that the cells look fairly normal, while grade 2 cells are growing a little faster, and grade 3 cells look markedly different than normal breast tissue.

These markers, along with the TNM measurements, define your stage.

A cancer recurrence refers to cancer that returns in the same breast, and it requires new staging. This new stage is marked by an “R” at the end to indicate “restaging.” If it develops in the other breast, it’s considered a new cancer.

The TNM system explained

TNM staging involves quite a bit of detailed information. Let’s break down this system:

T refers to the size of the tumor.

An imaging technique may be used to measure the tumor. The designations are:

• Tx: Tumor cannot be evaluated.
• T0: There’s no evidence of a tumor.
• Tis: This is carcinoma in situ, which means cancerous cells were caught before tumor growth.
• T1: Tumor is smaller than 2 cm across.
• T2: Tumor is 2 to 5 cm across.
• T3: Tumor is larger than 5 cm across.
• T4: Any size tumor is growing into chest walls or skin

N refers to spread to nearby lymph nodes.

Lymph nodes are pockets in your lymphatic system, which is similar to the circulatory system. Instead of blood, it transports a fluid called lymph. White blood cells are key immune cells that cluster in your lymph nodes, waiting to defend against foreign invaders. Cancer can spread to these nodes.

The cancer found in lymph nodes may be small (micrometastasis: 0.2 mm to 2 mm) or large (macrometastasis: bigger than 2 mm). The designations are:

• Nx: Lymph nodes cannot be evaluated.
• N0: There’s no evidence of spread.
• N1: Cancer has spread to a few axillary (underarm) lymph nodes or in smaller amounts to nodes near the breastbone.
• N2: Cancer has spread to more axillary lymph nodes than under N1 or made breastbone lymph nodes look bigger.
• N3: Cancer has spread significantly to axillary lymph nodes or may be near or above the clavicle (collarbone). Alternatively, fewer axillary lymph nodes are involved, but there are areas of macrometastasis (greater than 2 mm) and enlargement.

M refers to the spread to more distant parts of the body, or metastasis.

• Mx: Metastasis cannot be evaluated.
• M0: There’s no evidence of spread.
• M1: The cancer has spread to distant organs or tissues.

Putting it together

Your breast cancer stage is specific to you. It’s based on all the factors collected through diagnostic tests and/or surgery, and it helps your care team assess your prognosis.

The American Cancer Society offers examples of how to interpret a breast cancer stage. For example, a cancer that’s T2, grade 3, no spread to lymph nodes (N0) or body (M0), HER2-negative and ER- and PR-positive is stage 1B.

Next topic: How is breast cancer diagnosed?