breast cancer stages

Understanding The Different Stages of Breast Cancer

Breast cancer is the most common incidence of cancer. According to WHO, breast cancer impacts 2.1 million women each year and also causes the greatest number of cancer-related deaths among women.

Over 600 thousand deaths from breast cancer were recorded in 2018. Breast cancer is prevalent among women and very rare among men.

What is breast cancer?

Breast cancer is a cancer type where the cells in the breast grow out of control and form a malignant tumor that can be felt as lumps or seen on an x-ray in the breast.

Usually, cancer begins either in the lobule that produces the breast milk or the duct that transports the breast milk and sometimes, in the connective tissues of the breast.

It can spread to other parts of the body through the blood vessels and lymph vessels in a process called metastasized.

It is important to note that some breast lumps are non-cancerous. Non-malignant lumps are simply abnormal growths that occur in the body but they do not grow outside the breast and they are not deadly. However, some of these benign lumps can increase the risk of cancer.

So, it is necessary to immediately see a doctor if you discover any lumps in the breast, so they can determine if the lumps are cancerous or benign or if the non-malignant lumps increase the risk of cancer in the future.

It is also important to note that while many types of the breast cancer cause lumps in the breast, not all do. This is why periodical the importance of health checks cannot be overemphasized for early detection.

What are the 5 Stages of Breast Cancer?

Breast cancer is classified into different stages based on the extent of cancer that has affected the body and the severity of the situation.

Stage 0: Cancer is only in the lining of the breast duct and has not spread to the surrounding tissue of the breast. It is called Ductal Carcinoma in Situ (DCIS). It is also called non-invasive because cancer is still in the original place (in situ). But, if it is left untreated for long, it can spread outside the milk duct to the connective tissue of the breast.

Stage I: Cancer in this stage is called invasive, meaning it has spread to other surrounding tissues. There are two classifications of Stage 1

  • Stage IA: Although the tumor is invasive, it is small and has not spread to the lymph nodes and in some cases; there may be no tumor.
  • Stage IB: It means cancer has been found in the lymph nodes. The size of the cancer is no larger than 0.2mm but less than 2mm. The tumor in the lymph nodes is 20mm or lesser in size or there is no evidence of a tumor.

Stage II: At this stage, cancer has grown or spread. This stage is also classified into two sub-stages.

  • Stage IIA: At this stage, there is no evidence of tumor but cancer has spread to 1 to 3 lymph nodes under the arm (axillary lymph nodes) or in the lymph nodes inside the chest around the breastbone (internal mammary lymph nodes) or in both areas.
  • Stage IIB: The tumor in the breast is bigger. The tumor is larger than 20mm but not larger than 50mm and has spread to 1 to 3 axillary lymph nodes or it is larger than 50mm but has not spread to the axillary lymph nodes.

Stage III: Cancer, at this stage, is considered advanced and harder to treat but it has not spread to the bones or organs. There are three classifications of the third stage.

  • Stage IIIA: Cancer has spread or enlarged the lymph nodes deep in the breast. The cancer cells are found in 4 to 9 axillary lymph nodes, or in internal mammary lymph nodes but not in axillary lymph nodes. It could also be that the tumor is larger than 50mm that has spread to 1 to 3 axillary lymph nodes.
  • Stage IIIB: At this stage, the tumor has grown into the chest wall or skin around the breast, even if it hasn’t spread to the lymph nodes. Also, it may have spread to 1 to 9 axillary lymph nodes or to internal mammary lymph nodes. It could also have spread to 1 to 3 axillary lymph nodes and internal mammary lymph nodes. Again, inflammatory breast cancer is classified under Stage IIIB.
  • Stage IIIC: Cancer has spread to 10 or more axillary lymph nodes or to lymph nodes below the collarbone (infraclavicular lymph nodes). Also, cancer has spread to more than 3 axillary lymph nodes and internal mammary lymph nodes. Again, cancer could have spread to lymph nodes above the collarbone (supraclavicular lymph nodes).

Stage IV: At this stage, the cancer cells have spread from the breast and lymph nodes to other parts of the body, especially, to the brain, bones, liver, lungs, distant lymph nodes and chest wall. This process is called metastatic and so, this stage is also called metastatic breast cancer.

Recurrent breast cancer: As the term implies, recurrent breast cancer means that cancer has come back after treatment. This is also classified differently based on the part of the body that it appears.

  • Local recurrence: This describes cancer that reoccurs in the same place that cancer first started.
  • Regional recurrence: This is cancer that reoccurs in tissues or lymph nodes close to where it first started.
  • Distant recurrence: This is also called distant metastasis. It describes cancer that reoccurs in another part of the body.


Is breast cancer curable?

Breast cancer can be treated and treatment is targeted at causing cancer to shrink and to prevent it from spreading. Breast cancer that is detected early has a higher chance of being treated.

Breast Cancer Staging Calculator

There are different ways that doctors use to determine the stage of breast cancer; physical exams, biopsies, X-rays, bone scans and other images, and blood tests.

The TNM staging calculator is the most common tool that doctors use to finally determine the stage of breast cancer.

T (Tumour) – This determines how large the primary tumor is and where it is located. The “T” and a letter or number (0 to 4) is used to describe the size and location of the tumor.

TX: The primary tumor cannot be assessed.

T0: There is no evidence of cancer in the breast.

Tis: Refers to carcinoma in situ. The cancer is still in the original place. There are two types of breast carcinoma in situ:

  • Tis (DCIS): DCIS is non-invasive cancer because cancer cells have been found in breast ducts but have not spread past the layer of tissue where they began.
  • Tis (Paget’s): Paget’s disease of the nipple is a rare form of early, non-invasive cancer that is only in the skin cells of the nipple.

T1: The tumor in the breast is 20mm or smaller in size. The stage is classified into four sub-stages depending on the size of the tumor:

  • T1mi: A tumor that is 1mm or smaller
  • T1a: A tumor that is larger than 1mm but 5mm or smaller
  • T1b: A tumor that is larger than 5mm but 10mm or smaller
  • T1c is a tumor that is larger than 10mm but 20mm or smaller

T2: The tumor is larger than 20mm but not larger than 50mm.

T3: The tumor is larger than 50mm.

T4: The tumor falls into one of the following classifications:

  • T4a: The tumor has grown into the chest wall.
  • T4b: The tumor has grown into the skin.
  • T4c: Cancer that has grown into the chest wall and the skin.
  • T4d: It is used to describe inflammatory breast cancer.

N (Node) – This determines if the tumor has spread to the lymph nodes and if yes, where and how many. “N” could be lymph nodes under the arm (axillary lymph nodes) or lymph nodes inside the chest around the breastbone (internal mammary lymph nodes) or lymph nodes below the collarbone (infraclavicular lymph nodes) or lymph nodes above the collarbone (supraclavicular lymph nodes).

NX: The lymph nodes are not assessed.

N0: It is either no cancer was found in the lymph nodes or only areas of cancer smaller than 0.2mm are in the lymph nodes.

N1: Cancer has spread to 1 to 3 axillary lymph nodes and/or the internal mammary lymph nodes. 

N1mi: Cancer in the lymph node is larger than 0.2mm but 2mm or smaller. It is also called “micrometastatic”.

N2: Cancer has spread to 4 to 9 axillary lymph nodes or it has spread to the internal mammary lymph nodes, but not the axillary lymph nodes.

N3: Cancer has spread to 10 or more axillary lymph nodes or it has spread to the lymph nodes located under the clavicle or collarbone. It may have also spread to the internal mammary lymph nodes. Cancer could also have spread to the lymph nodes above the collarbone.

M (Metastasis) – The “M” describes whether cancer has spread to other parts of the body, called distant metastasis.

MX: Distant spread cannot be assessed.

M0: The disease has not metastasized.

M0 (i+): There is no clinical or radiographic evidence of distant metastases. However, microscopic evidence of tumor cells is found in the blood, bone marrow, or other lymph nodes that are no larger than 0.2mm.

M1: There is evidence of breast cancer cells growing in other organs.

Breast Cancer Treatment

Treatments are usually either or a combination of surgery, chemotherapy, hormone therapy, radiation or targeted therapies.

Surgery: The type of surgery usually depends on the diagnosis and individual inclination. Generally, the surgery is targeted at removing the tumors and sometimes, other affected tissues and parts of the breast. In some cases, reconstruction is necessary to make the breast look natural after surgery.

Chemotherapy: Chemotherapy drugs can be prescribed to destroy the cancer cells if there is a high chance of reoccurrence or spread. It could also be used before surgery to shrink the tumor so as to make removal easy during the surgery.

Hormone Therapy: This target of this treatment is to prevent hormone-sensitive breast cancers from reoccurring after surgery.

Radiation: This treatment is targeted at tumors to kill any remaining cancer cells.

Targeted Therapy: Targeted therapy is a newer and more effective treatment that destroys specific cancer cells without affecting normal cells. They are currently used alongside chemotherapy. At Oncopadi, you are not only provided with detailed information on cancer and also given the opportunity to consult with doctors on the different treatment options.

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