What are the Different Stages of Breast Cancer?

Breast Cancer Staging Explained – From Detection to Care

Breast cancer is a complex disease where abnormal cells in the breast grow uncontrollably and form tumours. These tumours can invade other parts of the body, and if doctors leave them untreated, they can become life-threatening. Breast cancer impacts many individuals worldwide, and early diagnosis is a crucial factor.

Therefore, understanding its stages is crucial for effective diagnosis, treatment, and management of the disease.

Staging System in Breast Cancer

In breast cancer, the stage refers to the extent of cancer in the body. The staging system used for breast cancer is the American Joint Council Committee on Cancer (AJCC) TNM system. It indicates the size of the tumour, whether cancer cells have spread to nearby lymph nodes, and if they have metastasised to other parts of the body.

Doctors use the TNM system to determine the stages. Here, TNM indicates:

• T (Tumour): Size and extent of the primary tumour.
• N (Nodes):Involvement of nearby lymph nodes.
• M (Metastasis):Spread to distant organs.

In addition to that, doctors consider factors like estrogen receptor status, HER2 status, and tumour grade in staging breast cancer.

The Clinical Stages of Breast Cancer

Let us take a look at the clinical stages of breast cancer and its features:

1. Stage 0 (Carcinoma in Situ)

• At this stage, abnormal cells are present but have not spread other than their original location where they started. It is considered a non-invasive breast cancer such as Ductal Carcinoma in Situ (DCIS) - abnormal cells in the lining of a breast duct. Early detection at this stage may lead to successful treatment outcomes.

2. Stage I (Early-Stage Invasive Breast Cancer)

Cancer cells have begun to invade surrounding breast tissue but are still relatively small. Stage I is divided into subcategories, which are known as IA and IB.

• In stage IA, the tumour is 2 cm or smaller and has not spread to lymph nodes.
• In stage IB, doctors find no tumour in the breast or a tumour that is 2 cm or smaller, and they discover small groups of cancer cells in lymph nodes.

Treatment of stage I may include surgery, radiation, and possibly hormone or targeted therapies.

3. Stage II (Locally Advanced Breast Cancer)

Stage II breast cancer is larger and may have spread to nearby lymph nodes. It is divided into other subcategories, such as IIA and IIB.

• In stage IIA, the tumour is 2 to 5 cm and may have spread to one to three lymph nodes. Doctors can find no tumour in the breast, but they may find cancer in one to two lymph nodes or the lymph nodes near the breastbone.
• In stage IIB, the tumour is larger than 2 cm but not larger than 5 cm and is found in lymph nodes. Also, the tumour is larger than 5 cm but has not spread to the axillary lymph nodes.

Treatment often involves a combination of surgery, chemotherapy, radiation, and hormone therapy.

4. Stage III (Regional Spread)

Cancer has spread more extensively within the breast and nearby areas but not to distant organs. We can divide stage III into IIIA, IIIB, and IIIC.

• In stage IIIA, a tumour of any size with cancer is found in four to nine axillary lymph nodes. If the tumour is larger than 5 cm, small groups of cancer cells invade the lymph nodes.
• In stage IIIB, the tumour can be any size and has spread to the chest wall or skin. Also, tumours have spread up to nine lymph nodes.
• In stage IIIC, cancer is in 10 or more lymph nodes or nodes near the collarbone.

This stage requires extensive treatment, including surgery, chemotherapy, radiation, and targeted therapies.

5. Stage IV (Metastatic Breast Cancer)

The cancer has advanced past the breast and nearby lymph nodes, spreading to other parts of the body, including the bones, liver, lungs, distant lymph nodes, and brain. Doctors use words like advanced and metastatic to describe stage IV breast cancer.

Early detection of breast cancer significantly improves treatment outcomes. Therefore, it is important to opt for regular screenings and checkups and be aware of breast changes, which are vital to take action accordingly.