What Is Stage 1 Breast Cancer?
Stage 1 is the earliest stage of invasive breast cancer, meaning the cancer has started spreading from its original location into nearby, healthy breast tissue.
Stage 1 is divided into two subcategories: Stage 1A and Stage 1B.
- Stage 1A:
The tumor is 2 centimeters (cm) or smaller and hasn’t spread outside the breast or to nearby lymph nodes. - Stage 1B:
There may be no visible tumor in the breast, or if there is one, it’s 2 cm or smaller. However, tiny clusters of cancer cells are found in nearby lymph nodes.
What Is Stage 2 Breast Cancer?
Stage 2 breast cancer means the cancer is growing, but it’s still confined to the breast or nearby lymph nodes. Like Stage 1, it has two subcategories: Stage 2A and Stage 2B.
- Stage 2A:
- No tumor is found in the breast, but cancer has spread to up to 3 lymph nodes near the breast or underarm.
- Or the tumor is 2 cm or smaller and has spread to the lymph nodes.
- Or the tumor is between 2 and 5 cm but hasn’t spread to the lymph nodes.
- Stage 2B:
- The tumor is between 2 and 5 cm and has spread to up to 3 lymph nodes near the breast or underarm.
- Or the tumor is larger than 5 cm but hasn’t spread to the lymph nodes.
What Is Stage 3 Breast Cancer?
Stage 3 breast cancer is considered more advanced. It means the cancer has spread more extensively within the breast and nearby lymph nodes but not to distant parts of the body. It’s broken down into Stage 3A, 3B, and 3C.
- Stage 3A:
- No tumor is found in the breast, or it can be any size.
- Cancer has spread to 4–9 lymph nodes under the arm or near the breastbone.
- In some cases, the tumor is larger than 5 cm and has spread to 1–3 lymph nodes.
- Stage 3B:
- The tumor may be any size.
- It has spread to the chest wall and/or the skin of the breast (which may cause swelling or ulceration).
- It may also involve up to 9 lymph nodes under the arm or near the collarbone.
- Stage 3C:
- The tumor may be any size.
- Cancer has spread to the chest wall and/or the skin, and to 10 or more lymph nodes, or to nodes near the collarbone or breastbone.
What Is Stage 4 Breast Cancer?
Stage 4 breast cancer, also known as metastatic breast cancer, means the cancer has spread far beyond the breast and nearby lymph nodes to other parts of the body.
Common areas where breast cancer spreads include:
- Bones
- Lungs
- Liver
- Brain
According to a 2017 study, bone metastasis was the most common (seen in about 65% of cases), followed by the lungs (31%), liver (26%), and brain (9%). About one-third of patients had cancer spread to multiple organs.
Symptoms of stage 4 breast cancer
depend on where the cancer has spread, but general signs may include:
- Constant fatigue
- Weakness
- Unexplained weight loss
- Pain in the area where cancer has spread (e.g., bones or joints)
