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Breast Cancer Stages

Treatment for breast cancer depends on the stage of the cancer. At the Abramson Cancer Center, our breast cancer pathologists and radiologists use their expertise to accurately stage breast cancer. The detailed information they provide ensures that you get the most appropriate treatment based on your diagnosis.

What Is Breast Cancer Staging?

After a breast cancer diagnosis, doctors assign a cancer stage based on the cancer’s location, tumor size and whether or not it has spread. Staging directs breast cancer treatment and may be a qualifying factor for some clinical trials.

How We Determine Breast Cancer Stages

We use advanced breast imaging, biopsy and diagnostic tests to assign a breast cancer stage. How we stage cancer depends on whether or not you’ve had breast cancer surgery. There are two types of staging for breast cancer:

  • Clinical staging: We stage cancer prior to surgery. The stage is based on a physical exam, nonsurgical biopsy and breast imaging.
  • Pathologic staging: We study tissue removed during breast cancer surgery. For advanced cancer, we also use information obtained from a sentinel lymph node biopsy. Whenever possible, we use pathologic staging, because it provides the most accurate picture of breast cancer.

Breast cancer staging depends on a number of factors, including:

  • Size of the tumor (T): How large is the area of cancer?
  • Spread to lymph nodes (N): Has the cancer spread to nearby lymph nodes?
  • Spread (metastasis) to distant sites (M): Has the cancer spread to other areas of the body?
  • Hormone receptor status: Is the cancer hormone-positive?
  • HER2 (human epidermal growth factor receptor 2) status: Is the cancer HER2-positive?
  • Grade of the cancer (G): How closely do cancer cells resemble normal cells?

We use this information to determine the most appropriate disease stage. Every breast cancer is unique, making staging a very complex process. Your breast cancer team can answer any questions about staging.

Stage 0 Breast Cancer

Cancer classified as stage 0 is only located in the breast ducts. It has not spread to surrounding tissue, lymph nodes or distant sites. This stage describes non-invasive types of cancer, such as ductal carcinoma in situ (DCIS).

Stage I Breast Cancer

Stage I cancer is the earliest stage for most types of invasive breast cancer (cancer that has spread to nearby tissue). Most stage I breast tumors are 2 centimeters or smaller. We divide stage I cancer into two categories (IA and IB). More advanced cancer may be classified as either stage IA or IB depending on the cancer’s hormone receptors and HER2-status.

Stage II Breast Cancer

Stage II breast cancer has not spread to distant sites. Stage II cancer is further classified (stage IIA and IIB) depending on the tumor size and any possible spread to lymph nodes. Cancer in this stage may have spread to lymph nodes under the arm and/or near the breastbone. Even if there is no spread to lymph nodes, cancer is often classified as stage II if the tumor is larger than 2 cm.

Stage III Breast Cancer

All inflammatory breast cancer is classified as stage III. Other types of cancer assigned to stage III may have larger tumors and/or advanced lymph node spread. Cancer that has grown into the chest wall or breast skin is considered stage III. We further classify breast cancer into stage IIIA, IIIB or IIIC. At this stage, the cancer has not spread to distant sites in the body.

Stage IV Breast Cancer

Stage IV breast cancer, commonly called metastatic breast cancer, has spread to distant organs or lymph nodes far from the breast. The most likely areas of spread are the bones, liver, brain and lungs. The initial breast cancer can be any size and may or may not have spread to nearby lymph nodes.