Breast cancer stage describes the extent of the cancer within your body.
The stage of your breast cancer helps plan your treatment.
Breast cancer stage is the most important factor for prognosis. In general, the earlier the stage, the better the prognosis will be.
Pathologic staging (the standard way to stage breast cancer) is based on a pathologist’s study of the tumor tissue and any lymph nodes removed during surgery.
Sometimes, results from a health care provider’s physical exam and/or tests such as mammography may help with staging.
The most widely used method of staging breast cancer is the TNM system.
TNM stands for:
In the past, tumor stage was classified using only these 3 measures. Starting in 2018, the TNM system added these measures:
Learn more about tumor size (T) and staging.
Learn more about lymph node status (N) and staging.
Learn more about metastases (M) and staging.
The new measures give specific information on the biology of the tumor that affects prognosis. Adding these measures improved staging.
For example, with breast cancer, a large tumor may have a better prognosis than a small tumor, based on biological measures. In the same way, a small tumor may have a worse prognosis than a large tumor based on these measures.
If you were diagnosed before 2018, your breast cancer was staged a bit differently than it would be today.
Find information on breast cancer staging before 2018.
If you will get neoadjuvant therapy (treatment, such as chemotherapy, before surgery), your breast cancer will be staged differently from someone who has surgery as a first treatment.
Neoadjuvant therapy can shrink tumors in the breast and/or lymph nodes, changing the original tumor size and lymph node status. So, your breast cancer is staged using information from physical exams, imaging and biopsies done before neoadjuvant therapy, rather than information from the tumor removed during surgery.
The stages shown in the table below are only used to classify breast cancers in people who have surgery as their first treatment.
If you will get neoadjuvant therapy, talk with your health care provider about how your breast cancer will be staged.
The stages of breast cancer range from 0 to IV (0 to 4).
The highest stage (stage IV) is any cancer with metastases (M1), no matter the size of the tumor, the lymph node status or other factor.
Most often, the higher the stage of the cancer, the poorer the prognosis will be.
The table below lists the TNM classifications for each stage of breast cancer for people who have surgery as their first treatment.
Tis N0 M0
T1* N0 M0
T0 N1mi M0
T1* N1mi M0
T2 N0 M0
T3 N0 M0
T0 N2 M0
T1* N2 M0
T2 N2 M0
T3 N1*** M0
T3 N2 M0
T4 N0 M0
T4 N1*** M0
T4 N2 M0
Any T N3 M0
*T1 includes T1mi.
**N1 does not include N1mi. T1 N1mi M0 and T0 N1mi M0 cancers are included for prognostic staging with T1 N0 M0 cancers of the same prognostic factor status.
***N1 includes N1mi. T2, T3 and T4 cancers with N1mi are included for prognostic staging with T2 N1, T3 N1 and T4 N1, respectively.
Used with permission of the American College of Surgeons, Chicago, Illinois. The original source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer International Publishing.
Oncotype DX is part of breast cancer staging for some estrogen receptor-positive, lymph node-negative tumors.
Learn more about Oncotype DX.
Facts for Life: Breast Cancer Prognosis
Breast Cancer 101 - Types and Staging
1-877 GO KOMEN(1-877-465-6636)