Stage 0
This stage is used to describe non-invasive breast cancer. There is no evidence of cancer cells breaking through to or invading neighboring normal tissue.
Stage 1
This stage describes invasive breast cancer (cancer cells are breaking through to or invading neighboring normal tissue) in which the tumor measures up to two centimeters, AND no lymph nodes are involved.
Stage 2
This stage describes invasive breast cancer in which the tumor measures at least two centimeters, but not more than five centimeters, OR the cancer has spread to the lymph nodes under the arm on the same side as the breast cancer.
Stage 3A
This stage describes invasive breast cancer in which the tumor measures larger than five centimeters, OR the tumor has spread to lymph nodes, and nodes are clumping or sticking to one another or surrounding tissue.
Stage 3B
This stage describes invasive breast cancer in which a tumor of any size has spread to the breast skin, chest wall, or internal mammary lymph nodes (located beneath the breast inside the chest), and includes inflammatory breast cancer.
Inflammatory Breast Cancer
Inflammatory breast cancer is a very uncommon but very serious type of breast cancer. The most distinguishing feature of inflammatory breast cancer is redness involving part or all of the breast. The redness feels warm. You may see puffiness of the breast's skin that looks like the peel of a navel orange ("peau d'orange"), or even ridges, welts, or hives. Part or all of the breast may be enlarged and hard. Inflammatory breast cancer is sometimes misdiagnosed as a simple infection.
Stage 4
This stage includes invasive breast cancer in which a tumor has spread beyond the breast, underarm, and internal mammary lymph nodes.