Breast cancer is one of the most common cancers among women in the United States. About 30% of all new cancer diagnoses in women are breast cancer. Approximately 13% of U.S. women will develop invasive breast cancer in their lifetime. Men can also get breast cancer, though it is much rare. Fortunately, after increasing for two decades breast cancer rates in the U.S. began to decrease in 2000. However, in recent years, incidence rates have increased slightly by about 0.5% per year.
Breast cancer remains a leading cause of cancer-related deaths among U.S. women, second only to lung cancer. For those with the condition, or for their loved ones, understanding the stages breast cancer goes through is an important part of treatment! Here is a guide to the 5 stages from PatientsLikeMe.
Determining the Stage
The stages of breast cancer describe how much the cancer has spread within the body. After a breast cancer diagnosis, doctors will assign a stage depending on a few factors. These factors can be described by the "TNM" system. This system is made up of:
- T - Tumor: Size (in centimeters)
- N - Node: Number of nearby lymph nodes with cancer
- M - Metastasized: Whether the cancer has metastasized or spread to other organs in the body
This system is an internationally accepted rubric for determining the stage of breast cancer. The stage then informs your treatment options.
The 5 Stages of Breast Cancer
Although it may be somewhat counterintuitive, staging for breast cancer starts at 0 and goes to 4. So there are 5 stages, but the counting of the stage does not begin with 1. Some of the stages have more than one form.
Stage 0
Here, the cancer cells are only in the ducts or lobules where they started and have not spread to nearby breast tissue. This stage is also called non-invasive cancer. The main type is ductal carcinoma in situ (DCIS).
Stage I
There are two forms of stage I breast cancer. In stage IA, the tumor is 2 centimeters (cm) or smaller and has not spread to the lymph nodes. In stage IB the tumor is 2 cm or smaller (or there may be no tumor in the breast), but small groups of cancer cells are found in the lymph nodes.
Stage II
In stage II the cancer is still in a limited region of the breast but has grown larger. In stage IIA there is either no tumor in the breast or there is a breast tumor up to 2 cm in size, plus the cancer has spread to lymph nodes under the arm. There could also be a tumor between 2-5 cm in the breast but no cancer in the lymph nodes. In stage IIB the tumor is between 2 cm and 5 cm and has spread to 1-3 lymph nodes. There could also be a tumor larger than 5 cm that has not spread to any lymph nodes.
Stage III
Stage III cancer is when the cancer has spread further into the breast or grown larger. There are three forms of this stage. In stage IIIA, there may or may not be a tumor but cancer is found in 4-9 lymph nodes. It can also be when a tumor is larger than 5 cm and the cancer has spread to between 1-3 lymph nodes. In stage IIIB the tumor has grown into the chest wall or skin, and may have spread to up to 9 lymph nodes. Stage IIIC is when the cancer has spread to 10 or more lymph nodes, or to lymph nodes above or below the collarbone, but has not spread to distant organs.
Stage IV
This is the last stage of breast cancer and the most advanced. Here, the cancer has spread to other parts of the body, such as bones, liver, lungs, or brain. This is also called advanced or metastatic breast cancer.
The stage of breast cancer helps doctors plan the best treatment and predict outcomes. If you or a loved one is diagnosed with breast cancer, talk about the stage and what it means with your healthcare team. They can explain the details and help guide you through the next steps in your treatment journey.