The old adage is true in that knowledge is power, and in the face of a breast cancer diagnosis, it’s crucial to have all of the necessary information for the most effective treatment. 

After a diagnosis has been made, a series of tests are given to determine the extent of the cancer, referred to as staging. The stage of the cancer diagnosed, according to the American Cancer Society, indicates if the cancer is invasive or non-invasive, the size of the tumor, how many lymph nodes are affected or if the cancer has spread to other parts of the body. 

Determining the stage of the cancer is critical in establishing the most viable treatment options, as well as offering the patient a prognosis of the disease. Both ACS and the National Cancer Institute offer comprehensive breakdowns of the staging system and factors in which every stage is based around. The stages include Stage 0 (non-invasive), I, II, IIIA, IIIB, IIIC and IV. In order to determine the stage of the cancer, there are a number of different tests that may be given, including a sentinel lymph node biopsy, chest X-ray, CAT (or CT) scan and PET scan. 

The NCI states there are three ways in which cancer can spread throughout the body; it may spread through tissue by growing in surrounding areas, through the lymph system by traveling through the lymph vessels and through blood. The spreading of cancer in the body is called metastasis. Should the cancer spread, a metastatic tumor will form and no matter the target zone of the new tumor, it will consist of the same type of cancer cells of the primary tumor. 

According to the ACS, the staging system is standardized in order for cancer health-care teams to collect the most comprehensive information on how the cancer has spread. The American Joint Committee on Cancer offers a TNM system which is commonly used. The stages are based on their TNM classifications. The T, followed by a number ranging from 0 to 4, described the size of the tumor and the spreading to the skin or chest wall under the breast. The N, which is also followed by a number ranging from 0 to 3, determines if the cancer has spread to the lymph nodes and if so, how many. The M, followed by a 0 or 1, indicates if the cancer has spread to other organs.

Stage 0, which is non-invasive cancer, is considered pre-cancer of the breast. The ACS describes this stage in which cancer cells are present in a duct but not yet in the surrounding breast tissue. 

Stage I indicates the cancerous tumor is no bigger than 1 inch, or about 3/4 of an inch, and it has not spread to outside of the breast. It is possible in Stage IB that small clusters of cancer cells, no larger than 2 millimeters, may be found in the lymph nodes, according to the NCI. 

In Stage II there may be a number of varying factors; the cancerous tumor may not be larger than one inch but has spread to lymph nodes under the arm, the tumor is between 1 and 2 inches and may or may not have spread to the lymph nodes or the cancer is larger than 2 inches but has not spread. Stage II is split into Stage IIA and Stage IIB.

Stage III is divided into three stages – IIIA, IIIB and IIIC. Stage IIIA may indicate that the cancer size is under 2 inches but is spreading to the lymph nodes under the arm; the cancer is spreading further into more lymph nodes or the cancer is larger than 2 inches and is also spreading to lymph nodes under the arm, according to the University of California San Francisco Medical Center. Stage IIIB might indicate that the cancer has spread to tissue near the breast or the cancer has spread to lymph nodes inside the chest wall near the breastbone. Stage IIIC may be divided into operable and inoperable, according to the NCI, and might indicate that the cancer has spread to the skin of the breast and/or the chest wall, as well as nearby and surrounding lymph nodes. 

Stage IV breast cancer is considered the most advanced stage. In this stage, the cancer has spread to other parts of the body such as the bones, lungs, liver or brain, according to the UCSF Medical Center. It may also have spread to the skin or into the lymph nodes in the
neck. 

The ins and outs of breast cancer and breast cancer treatment may feel complicated or overwhelming, so it’s important to discuss with your doctor and healthcare team all of the available treatment options. 

To be best prepared in asking all of the important questions, more information on the stages of breast cancer can be found at www.cancer.gov or www.cancer.org.