Breast Cancer Stages

Early Stage Breast Cancer

Early stage breast cancer refers to stages 0-III. 






Staging is a standard term used across the medical profession to communicate widespread or advanced the cancer is in the breast tissue and possibly other parts of your body.  The staging of your tumor helps doctors explain the breadth and scope of the cancer and determine how to move forward with treatment, including surgery, if needed.  


Doctors use diagnostic tests to find out the cancer's stage, so staging may not be complete until all the tests are finished.

Stages of Breast Cancer.

The stage of a breast cancer is determined by the cancer’s characteristics, such as how large it is,  where the tumor is located within the breast tissue, and if it has spread to the lymph nodes or other parts of the body.  In addition to helping your doctor determine your treatment plan, the stage of the cancer helps you and your doctor:

•         Figure out your prognosis, the likely outcome of the disease

•         Determine if certain clinical trials may be a good option for you


Breast cancer stage is usually expressed as a number on a scale of 0 through IV — with stage 0 describing non-invasive cancers that remain within their original location and stage IV describing invasive cancers that have spread outside the breast to other parts of the body.  

Clinical vs. Pathological Staging

Clinical staging is based on the results of tests done prior to surgery.  If your biopsy comes back positive, your doctor may order additional tests to garner a better understanding if and where the cancerous cells have spread.  This data gathering period may include physical examinations, mammogram, ultrasound, and MRI scans.  In some cases your doctor may also order a bone or CT scans. 


Pathologic staging is based on what is found during surgery to remove breast tissue and lymph nodes.  While a lot of the aforementioned tests can provide your oncological team with lots of information and data points, it is not until surgery is preferred where the surgeons can go remove tumor and possible lymph nodes in order to confirm the size of the tumor, the number of lymph node involvement, and whether or not the cancer has metastasized. 

Early Stage Breast Cancer

Early stage breast cancer refers to stages 0-III. 

Stage 0

Stage 0 cancers are called “carcinoma in situ.” Carcinoma means cancer and “in situ” means “in the original place.” Types of “in situ carcinoma” include

  • DCIS – Ductal carcinoma in situ

  • LCIS – Lobular carcinoma in situ

  • Paget disease of the nipple

Stage I

Stage 1 can be divided into Stage 1A and Stage 1B. The difference is determined by the size of the tumor and the lymph nodes with evidence of cancer.

Stage II

Stage II means the breast cancer is growing, but it is still contained in the breast or growth has only extended to the nearby lymph nodes.

This stage is divided into groups: Stage 2A and Stage 2B. The difference is determined by the size of the tumor and whether the breast cancer has spread to the lymph nodes.

Stage III

Stage 3 cancer means the breast cancer has extended to beyond the immediate region of the tumor and may have invaded nearby lymph nodes and muscles, but has not spread to distant organs.  


This stage is divided into three groups: Stage 3A, Stage 3B, and Stage 3C. The difference is determined by the size of the tumor and whether cancer has spread to the lymph nodes and surrounding tissue.

TNM Staging System

Doctors use the TNM system to ensure that medical professionals are using the same language and system to describe the tumor. 

T refers to the size of the tumor measured in centimeters and where it is located.

N refers to the number of lymph nodes which were positive for cancer. If no lymph nodes were involved, the pathology report would state N(0).

M refers to whether or not the cancer has traveled to distant part of the body such as the bones or organs. If it has spread, it will state where and how much. 

For example, stage IIB may read something like this:  (T3, N0, M0) meaning the tumor is greater than 55mm and has not spread to the lymph nodes or other parts of the body. 

Updated Staging Guidelines

In 2018, the AJCC updated the breast cancer staging guidelines to add other cancer characteristics to the T, N, M system to determine a cancer’s stage.


In addition to knowing the stage of your cancer, breast cancer is also classified according to other characteristics. These include how sensitive it is to the hormones estrogen and progesterone as well as to the level of certain proteins that play a role in breast cancer growth, such as HER2. It is also classified by the cancer’s genetic makeup.

  • Tumor Grade: a measurement of how much the cancer cells look like normal cells

  • HER2 status: are the cancer cells making too much of the HER2 protein?

  • Oncotype DX score, if the cancer is estrogen-receptor-positive, HER2-negative, and there is no cancer in the lymph nodes

"The updated guidelines mean that staging is now catching up to how people are actually treated,” explained Elizabeth Mittendorf, M.D., Ph.D., Rob and Karen Hale Distinguished Chair in Surgical Oncology and director of the Breast Immuno-Oncology Program at the Dana-Farber Cancer Institute, who served on the expert panel that wrote the updated guidelines.

Additional information on staging can be found on the resource links below:

Follow Us
  • Facebook
  • Twitter
  • YouTube
  • Pinterest
  • Instagram