Breast Cancer Awareness Month: What Are The Four Stages Of Breast Cancer?

October is the breast cancer awareness month and it focuses on the importance of awareness around that. When someone is diagnosed with breast cancer, the staging then establishes the characteristics and the treatment the patient would require.

How Is Staging Determined?

As per the American Cancer Society (ACS), the most common staging system is made by the American Joint Committee on Cancer, known as the TNM system.

T refers to the size of the tumor, N indicates to whether or not the cancer has spread to nearby lymph nodes, and M denotes if the cancer has spread to more distant lymph nodes or other organs of your body.

The system was later also updated to consider factors like hormone receptors like HER2, grade of cancer and the gene expression tests.

Stages of cancer

The stages of cancer are between 0 to 4. Stage 0 breast cancer is described as noninvasive breast cancer that is also called the ductal carcinoma in situ. This is where the cancerous cells are found in the ducts of your breast but have not yet invaded further in the breast tissue.

Stage 1 Breast Cancer

This is the first stage in the invasive breast cancer, when the cancer cells start to spread from their initial location to noncancerous breast tissues.

It is further divided into 1A and 1B. 1A cancers are tumors that are no more than 2 centimeters in size and has not spread outside your breast tissues or lymph nodes. Whereas 1B may not be a detectable tumor in your breast, it could be smaller than 2 centimeters and can form groups in nearby lymph nodes.

Stage 2 Breast Cancer

Here two there are two types, 2A where there are no tumors, or if there is a tumor, it is smaller than 2centemeter. However, the cancer cells have spread up to three lymph nodes or under your arm or near your breastbone.

In stage 2B the tumor is between 2 to 5 centimeters in size and small groups of cells can be found in nearby lymph nodes.

Stage 3 Breast Cancer

In some cases in stage 3A the tumor may not be detected in the breast or if there is a tumor, the size can vary. The cancer by now may have spread between four and nine lymph nodes under your arms or near your breastbone.

In stage 3B, it can spread to your chest wall and skin of your breast and even around your collarbone's lymph nodes.

In stage 3C, the tumor can spread to your arm, collarbone and to 10 or more lymph nodes.

Stage 4 Breast Cancer

This means that the cancer has spread beyond your breast and nearby lymph nodes and into distant lymph nodes and tissues. It is also referred to as metastatic breast cancer.

According to the National Cancer Institute (NCI), the most common areas of the body for breast cancer to spread at this stage are your bones, brain, liver, lung.

As per a 2017 study, people with stage 4 cancer found that metastasis to the bones was most common with 65.1% of the participants with the same cancer spread. While the lung is the next common site with 31.4%, liver at 26% and brain at 8.8%.