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Stages of Breast Cancer and Other Prognostic Factors

Stages of Breast Cancer

The stages of breast cancer refer to a combination of several pieces of pathology information, including:

  • Diameter of the (invasive) tumor
  • Nodal involvement (if lymph nodes under the arm have been affected and how many are affected)
  • Other organ involvement (lung, bone, liver, brain)

Staging is important because it helps us create an individualized treatment plan for each patient.

Early Breast Cancers

Stage 0 Breast Cancer – This is noninvasive breast cancer, or DCIS. Cancer cells are limited to the lining of the ducts and have not spread beyond the duct.

Stage I (IA/B) Breast Cancer – The cancer has spread from the ducts or lobules into the nearby fatty tissue of the breast. The tumor diameter is less than 2 centimeters and there is no cancer in the lymph nodes.

Stage II (IIA/B) Breast Cancer – The cancer has spread from the ducts or lobules into the nearby fatty tissue of the breast. The tumor diameter is between 2 and 5 centimeters. At this stage the cancer may have spread to the nearby lymph nodes.

Advanced Breast Cancers

Stage III (IIIA/B) Breast Cancer – The tumor may be larger than 5 centimeters and the cancer may or may not have spread to the nodes, or the tumor is smaller with several nodes involved. Stopping the spread of the cancer is a major concern. A diagnosis of inflammatory breast cancer is classified as stage III breast cancer.

Stage IV/Metastatic Breast Cancer – The cancer has spread from the breast and lymph nodes to other parts of the body; there are usually organs involved, including the lungs, liver, bones and/or brain.

Grade and Rate of Growth

Predicting the cancer cell’s speed and way of growing is an important consideration in categorizing a patient’s breast cancer.

Rate of growth – S-phase fraction and Ki67 tests will likely be performed to measure cell growth. These tests are not always accurate, so other factors will also be used to make decisions.

Patterns of cell growth – How a cancer grows is measured on a scale of one to three, one for a cancer that grows slowly or predictably and three for a cancer that is more irregular in its growth pattern.

Necrosis/dead cells – The presence of “dead cells” is one sign that the tumor has aggressive growth.

Lymphatic invasion – If the tumor cells have gotten into the fluid channels of the breast, they are categorized this way. These cancers have an increased risk of spreading beyond the breast to lymph nodes and/or to other organs within the body.

Hormone Receptors

Estrogen and progesterone receptors are another key factor in breast cancer cell growth. Your pathology report will determine if your cancer is estrogen receptor (ER) positive or negative, or progesterone receptor (PR) positive or negative. Positive hormone receptive cancers are more likely to respond to anti-estrogen therapies, like Tamoxifen or an aromatase inhibitor. Hormone negative cancers may respond to other types of treatments.

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HER2 Oncogenes

HER2 is a cancer gene that creates extra HER2 protein receptors in some breast cancers and is then called HER2 positive disease. This behavior can lead to an aggressive cancer, and used to be considered the most aggressive form of breast cancer.  However, the development and use of biologic targeted therapies such as trastuzumab (Herceptin), has made HER2 positive disease easier to treat.  

Biologic tarteted therapy