Breast cancer - Staging and grading breast cancer

Breast cancer

Staging and grading breast cancer

If you have breast cancer, your doctor will need to know how serious it is. To do this, your doctor will figure out the stage of your cancer and possibly the grade of your cancer. Knowing your stage and grade will help your doctor decide which treatments are best for you.

Staging your cancer

TNM (tumor, node, metastasis)

When your breast cancer is staged, it is classified according to three things.

How big your breast cancer (tumor) is, and whether it has spread from the breast tissue into the nearby skin and muscles.
Whether your breast cancer has spread to your

lymph nodes
Lymph nodes (also called glands) are small, bean-shaped lumps that you cannot usually see or easily feel. They are located in various parts of the body, such as the neck, armpit and groin. Lymph nodes filter the lymph fluid and remove unusual things, such as bacteria and cancer cells.

lymph nodes (these small collections of cells are part of your

immune system
The immune system is made up of the parts of the body that are devoted to fighting infection. The body is constantly being threatened by infections from things like bacteria, viruses and parasites. The immune system fights these infections in different ways. At the microscopic level, the immune system uses antibodies and white blood cells, which travel in the blood and target infectious agents, such as bacteria. These microscopic parts of the immune system either kill the infectious agent directly, or take it to other parts of the body, like the spleen, where it can be dealt with. The lymph nodes are another important part of the immune system. Within them, white blood cells filter through the foreign material that has entered the blood, to see if there are any infections. When you have a swollen gland during a cold, this is actually a lymph node that is reacting to the infection. Unfortunately, it is possible for the immune system to become confused and to use its destructive powers to target healthy parts of the body. Diseases that result from this type of situation are called autoimmune diseases.

immune system).
Whether your breast cancer has spread to other parts of your body.

These three things are used together and called the TNM classification:

Source:
Sobin LH, Wittekind CH.
TNM: classification of malignant tumours.
In: International union against cancer. 5th Edition. Wiley-Liss, New York, US; 1997.

T is for tumor
N is for (lymph) nodes
M is for metastasis. (Metastasis is when the cancer spreads to other parts of your body, such as your liver or lungs.)

Each factor is given a number.

For T, the number tells you how big the tumor is.
For N, the number shows which lymph nodes have cancer cells in them.
For M, the number tells you whether your breast cancer has spread outside your breast and the nearest lymph nodes to other parts of your body.

Generally, lower numbers mean your cancer is less serious. For example, if your cancer was classified as T1N0M0, this would show that you had a small tumor that had not spread to the lymph nodes nearest to it or to other parts of your body.

Here's what the different classifications mean.

T (tumor)

Tis: This is also called cancer in situ or carcinoma in situ. It means your breast cancer hasn't spread beyond the lining of the ducts.
T1: Your breast cancer is 2 centimeters (around three-quarters of an inch) or less across.
T2: Your breast cancer is more than 2 centimeters (around three-quarters of an inch) but no bigger than 5 centimeters (around 2 inches) across.
T3: Your breast cancer is bigger than 5 centimeters (around 2 inches) across.
T4: Your tumor extends from the breast into your chest wall or your skin. Or the tumor is inflammatory. (Inflammatory cancer is a rare, invasive cancer that can block the

lymph vessels
Lymph vessels are part of your body's lymphatic system. This system moves lymph fluid through your body. This fluid carries proteins, white blood cells and other substances. Lymph vessels carry fluid between your lymph nodes.

lymph vessels in the skin over the breast.)

N (lymph nodes)

N0: Your breast cancer has not spread to the nearest lymph nodes (local lymph nodes).
N1: Your breast cancer has spread to the lymph nodes on the same side of your body as your breast cancer, and these can be moved around (they are not joined together by the cancer).
N2: Your breast cancer has spread to lymph nodes that can't be moved (they are joined together by the cancer) on the same side of your body as your breast cancer.
N3: Your breast cancer has spread to lymph nodes toward the middle of your body (the internal mammary nodes) on the same side as your breast cancer.

M (metastasis)

M0: Your breast cancer has not spread to another part of your body.
M1: Your breast cancer has spread to a distant part of your body. This is called metastasis. This may mean it has spread to lymph nodes above the collarbone on the same side of your body as your breast cancer, or to your bones, liver or lungs.

Stages of breast cancer

Once your doctor has your TNM classification, he or she uses it to figure out your cancer stage. Doctors divide cancer into four main stages. Most doctors use the American Joint Committee on Cancer staging system.

Source:
American Joint Committee on Cancer Staging.
AJCC cancer staging manual: colon and rectum.
5th edition. Lippincott-Raven, Philadelphia; 1997.

Stage 1

Stage 1 breast cancer means:

The tumor (lump or patch of cancer cells) is no more than 2 centimeters (around three-quarters of an inch) across
The lymph nodes in the armpit aren't affected
The cancer hasn't spread to another part of the body
This is often called early breast cancer.

Stage 2

Stage 2 breast cancer means that the tumor is bigger than 2 centimeters (around three-quarters of an inch) but smaller than 5 centimeters (around 2 inches), or the lymph nodes in the armpit are affected. It also means that the cancer hasn't spread to another part of the body.

When the tumor is 2 centimeters (around three-quarters of an inch), this is often called early breast cancer.
When the tumor is closer to 5 centimeters (around 2 inches), this is often called locally advanced breast cancer.

Stage 3

Stage 3 breast cancer means:

The tumor is bigger than 5 centimeters (around 2 inches) across
The cancer is in the nodes in the armpit
The cancer hasn't spread to another part of the body
This is often called locally advanced breast cancer.

Stage 4

Stage 4 breast cancer means:

The tumor can be any size
The cancer is in the nodes in the armpit
The cancer has spread to other parts of the body
This is often called metastatic or secondary breast cancer.

Doctors also divide some of these stages further. For example, stage 2 is divided into 2A and 2B. To read more about how doctors stage cancer using the TNM system and American Joint Committee on Cancer staging system, see Cancer staging table.

Grading your cancer

Your doctor may also tell you about the grade of your cancer. The grade describes how much the cancer cells look like normal breast cells when viewed under a microscope.

Doctors usually grade cancer as low grade or high grade. Low-grade cancer cells look similar to normal cells. High-grade cancer cells look very different from normal breast cells.

The more the cells look like normal cells, the better your outlook may be. You may also hear your cancer grade described as a number between 1 and 4. A lower number means a lower grade.

You and your doctor can use information about the size of your breast cancer, whether it has spread to your lymph nodes, and what it looks like under a microscope to discuss the best treatment for you.

Sources for the information on this page:

Sobin LH, Wittekind CH.TNM: classification of malignant tumours.In: International union against cancer. 5th Edition. Wiley-Liss, New York, US; 1997.

American Joint Committee on Cancer Staging.AJCC cancer staging manual: colon and rectum.5th edition. Lippincott-Raven, Philadelphia; 1997.

This information was last updated on May 11, 2009

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
© BMJ Publishing Group Limited 2009. All rights reserved.

The information on ConsumerReportsHealth.org should not be viewed as a substitute for a consultation with a medical or health professional. The information is meant to enhance communication with your doctor, not replace it. Consumers Union can not be liable for any loss, injury, or other damages related to your use of this information.

Your use of this information is subject to our User Agreement available at www.ConsumerReportsHealth.org.