Most forms of breast cancer begin as a type of carcinoma (which is a cancer of the cells that line all of the tissues in the body) that originates in either the ducts that bring breast milk over to the nipple or in the lobules, where breast milk is produced. While the ducts are the most common source of cancer formation, breast cancer can and will form anywhere in the breast or surrounding tissues.
Once cancer has been found, doctors need to determine where the disease is at in terms if progression and scope. In order to ascertain what stage a cancer may be, doctors refer to a system called TNM. In this system, the “T” stands for the size of the tumor – whether it is large or small; the “N” stands for whether or not nearby lymph nodes have been affected and diseased with cancer as well; and the “M” stands for metastasis, which determines if the cancer is spreading, where it is spreading, and how aggressively it is spreading.
- TX indicates that the tumor is not able to be either be measured or found.
- T0 indicates there is no hard any evidence of a principal tumor.
- Tis indicate the cancer is “in situ” – in other words, the tumor has not yet begun to invade surrounding breast tissue.
- T1, T2, T3, T4: This number system is based on the size of the tumor and the extent to which it has invaded the surrounding tissues. The bigger the number, the bigger the tumor or the more it has invaded and metastasized.
- MX indicates metastasis is not able to be be measured or located.
- M0 indicates there is no far-reaching metastasis, only localized metastasis.
- M1 indicates that far-reaching metastasis is present.
Stage Zero
Stage Zero breast cancer is the very beginning stages of the disease. It is also known as ductal or lobular carcinoma in situ. Cancer at this stage of the game has not moved or metastasized to any other areas of the body other than where it originated. This is the same reason that Stage Zero cancer is also known as a non-invasive cancer.
Stage I
Stage I breast cancer is deemed invasive because it has invaded another area of tissue – this is true even if the newly affected area is in immediate proximity to the place of origin. Additionally, if the cancerous tumor is 2 centimeters in size or less, and if there is no lymph-node involvement, then it still qualifies as Stage 1 cancer.
Stage II
Stage II breast cancer has two sub-stages: stages, IIA and IIB.
In order to qualify for the first, one of the following must be true:
- There is no cancer found in the actual tissue of the breast, but cancer cells have been detected found in the nearby underarm lymph nodes.
- There is a tumor that measures 2 centimeters (or smaller) that has spread to nearby lymph nodes.
- There is a tumor measuring between 2 and 5 centimeters located in the breast tissue that has not spread to the neighboring lymph nodes.
In order to qualify for the second sub-stage, one of the following must be true:
- There is a tumor measuring between 2 and 5 centimeters that has spread to the lymph nodes.
- There is a tumor measuring more than 5 centimeters that has not spread to the lymph nodes.
Stage III
Stage III breast cancer, like Stage II, is broken into sub-stages.
In order to qualify for Stage IIIA, one of the following must be true:
- There may be no cancer found in the breast, but there are cancer cells located in the armpit lymph nodes and/or in the lymph nodes near the collarbone.
- There is a tumor in the breast tissue that has also spread to nearby lymph nodes.
In order to qualify for Stage IIIB, one of the following must be true:
- A tumor of any size in the breast tissue that has spread to the chest or to the skin of the breast and/or has spread to armpit lymph nodes or any other lymph nodes near the collarbone.
- Inflammatory breast cancer is present.
In order to qualify for Stage IIIC, one of more of the following must be true:
- There may or may not be cancer in the breast itself, but if a tumor is present it can be any size and will also have spread to the chest or the breast’s skin, as well as to the nearby lymph nodes in either the armpit of collarbone.
Stage IV
The final stage of breast cancer is Stage IV, which occurs when the breast cancer has passed through each previous stage and has aggressively metastasized to different parts of the body. Treatment of this form of breast cancer usually focuses on merely relieving the symptoms that are already present. In occasional cases, an especially aggressive form of breast cancer can spread to other areas of the body without first spreading to nearby lymph nodes. In some cases, breast cancer that advances like this may be able to seep into the blood stream as well.
No matter what stage of cancer you or someone you know may be facing, your pathology report and any additional tests you may have had will provide information about the breast cancer stage you are experiencing. It should also indicate whether or not the cancer has spread and what parts of the body may also be affected.
After this determination, your doctor will be able to create a treatment plan that is unique to your situation. If your cancer requires a biopsy or even a tumor removal surgery, there is a very good chance that they will also take a look at the nearby lymph nodes to check for cancer cells, since that is the most common path that metastasizing breast cancer takes. At this point your doctor will likely call for additional blood or imaging tests to determine where else the cancer may have spread to and to get a better handle on how aggressive the cancer is becoming. This will aid in determining an exceptionally tailored treatment and recovery plan.