How many stages are there in breast cancer?

Stage is usually expressed as a number on a scale of 0 through IV — with stage 0 describing non-invasive cancers that remain within their original location and stage IV describing invasive cancers that have spread outside the breast to other parts of the body.
Stage 0
Stage I
Stage II
Stage III
Stage IV

Cancer stage is based on four characteristics:

• The size of the cancer
• Whether the cancer is invasive or non-invasive
• Whether cancer is in the lymph nodes
• Whether the cancer has spread to other parts of the body beyond the breast

You also may see or hear certain words used to describe the stage of the breast cancer:
Local: The cancer is confined within the breast.
Regional: The lymph nodes, primarily those in the armpit, are involved.
Distant: The cancer is found in other parts of the body as well.
Sometimes doctors use the term “locally advanced” or “regionally advanced” to refer to large tumours that involve the breast skin, underlying chest structures, changes to the breast's shape, and lymph node enlargement that is visible or that your doctor can feel during an exam.