Breast Cancer Stages

Cancers are divided into different groups, called stages, based on whether the cancer is invasive or non-invasive, the size of the tumor, how many lymph nodes are involved, and whether there is spread to other parts of the body.

Staging a cancer is the process of finding out how far the cancer has progressed when it is diagnosed. Doctors determine the stage of a cancer by gathering information from physical examinations and tests on the tumor, lymph nodes, and distant organs.

A breast cancer’s stage is one of the most important factors that may predict prognosis (outlook for cure versus the chance of cancer coming back or spreading to other organs). A cancer’s stage, therefore, is an important factor in choosing the best treatment.

Each woman’s outlook with breast cancer differs, depending on the cancer’s stage and other factors such as hormone receptors, her general state of health, and her treatment.

You should talk frankly with your doctors about your cancer stage and prognosis, and how they affect treatment options.

System To Define Cancer Stage

The system most often used to describe the extent of breast cancer is the TNM staging system. In TNM staging, information about the tumor (T-Stage), nearby lymph nodes (N-Stage), and distant metastases (M-Stage) is combined and a stage is assigned to specific TNM groupings. The TNM stage groupings are described using Roman numerals from 0 to IV.

The clinical stage is determined by what the doctor learns from the physical examination and tests. The pathologic stage includes the findings of the pathologist after surgery. Most of the time, pathologic stage is the most important stage since involvement of the lymph nodes can only be accurately determined by examining them under a microscope.

T stands for the size of the cancer (measured in centimeters: 2.5 centimeters = 1 inch) and whether it is growing directly into nearby tissues. N stands for spread to nearby lymph nodes and M is for metastasis (spread to other parts of the body).

Categories of T; N; M

Tumor Sizes 2.5 centimeters (cm) = 1 inch, 1cm = 10mm

T categories
T categories are based on the size of the breast cancer and whether it has spread to nearby tissue.

• Tis: Tis is used only for carcinoma in situ or noninvasive breast cancer such as ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS).
• T1: The cancer is 2 cm in diameter (about 3/4 inch) or smaller.
• T2: The cancer is more than 2 cm but not more than 5 cm in diameter.
• T3: The cancer is more than 5 cm in diameter.
• T4: The cancer is any size and has spread to the chest wall or the skin.

N categories:
The N category is based on which of the lymph nodes near the breast, if any, are affected by the cancer. There are 2 classifications used to describe N. One is clinical — before surgery — in other words, what the doctor can feel or see on imaging studies. The other is pathological — what the pathologist can see in lymph nodes removed during surgery.

• N0 Clinical: The cancer has not spread to lymph nodes, based on clinical exam.
• N0 Pathological: The cancer has not spread to lymph nodes, based on examining them under the microscope.
• N1 Clinical: The cancer has spread to lymph nodes under the arm on the same side as the breast cancer. Lymph nodes are not attached to one another or to the surrounding tissue.
• N1 Pathological: The cancer is found in 1 to 3 lymph nodes under the arm.
• N2 Clinical: The cancer has spread to lymph nodes under the arm on the same side as the breast cancer and are attached to one another or to the surrounding tissue. Or the cancer can be seen to have spread to the internal mammary lymph nodes (next to the sternum), but not to the lymph nodes under the arm.
• N2 Pathological: The cancer has spread to 4 to 9 lymph nodes under the arm.
• N3 Clinical: The cancer has spread to lymph nodes above or just below the collarbone on the same side as the cancer, and may or may not have spread to lymph nodes under the arm. Or the cancer has spread to internal mammary lymph nodes and lymph nodes under the arm, both on the same side as the cancer.
• N3 Pathological: The cancer has spread to 10 or more lymph nodes under the arm or also involves lymph nodes in other areas around the breast.

M categories:
The M category depends on whether the cancer has spread to any distant tissues and organs.

• M0: No distant cancer spread.
• M1: Cancer has spread to distant organs.

Stage grouping for breast cancer

Once the T, N, and M categories have been assigned, this information is combined to assign an overall stage of 0, I, II, III or IV as seen in the table below. The stages identify tumor types that have a similar outlook and are treated in a similar way.

BREAST CANCER WORK-UP

BREAST CANCER TREATMENT

For more information on these treatment guidelines, or on cancer in general, call the NCCN at 1-888-909-NCCN or the American Cancer Society at 1-800-ACS-2345. Or you can visit these organizations’ web sites at www.cancer.org (ACS) and www.nccn.org (NCCN).

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