The stages of breast cancer range from 0 to IV
- in proper usage, 'stage' describes the cancer at diagnosis, although 'stage' is also loosely used to describe cancer progression
- for example, a stage II cancer is sometimes said to have progressed to become stage IV (but not stage III)
- Stage 0 breast cancer (ductal carcinoma in situ) is in a class of its own
- Stage IV is also an outlier, being based entirely on the presence or absence of metastatic disease at diagnosis (The assumption is that, in the presence of metastatic disease, size and axillary nodes are irrelevant)
- the three intermediate stages (stages I-III) are based on tumour size and the presence or absence of involved lymph nodes. If patients with ductal carcinoma in situ or with metastatic disease are excluded, staging in its basic form is a simple transformation in which the elements of a 3×2 table are reduced to a single variable with 3 possible values
The stages have been further classified. The description below is designed to be appropriate to help with communication about breast cancer stage with patients:
- Stage 0
- Stage 0 is used to describe non-invasive breast cancers, such as DCIS (ductal carcinoma in situ)
- Stage I
- Stage I describes invasive breast cancer (cancer cells are breaking through to or invading normal surrounding breast tissue)
- Stage I is divided into subcategories IA and IB
- Stage IA describes invasive breast cancer in which:
- the tumor measures up to 2 cm AND
- the cancer has not spread outside the breast; no lymph nodes are involved
- Stage IB describes invasive breast cancer in which:
- there is no tumor in the breast; instead, lymph nodes involvement of larger than 0.2 mm but not larger than 2 mm - are found,
- OR there is a tumor in the breast that is no larger than 2 cm, and there is lymph node involvement of - larger than 0.2 mm but not larger than 2 mm
- microscopic invasion is possible in stage I breast cancer. In microscopic invasion, the cancer cells have just started to invade the tissue outside the lining of the duct or lobule, but the invading breast cancer is less than than 1 mm
- Stage II
- Stage II is divided into subcategories known as IIA and IIB
- Stage IIA describes invasive breast cancer in which:
- no tumor can be found in the breast, but evidence of breast cancer in axillary nodes OR
- the tumor measures 2 cm or smaller and has spread to the axillary lymph nodes
- OR the tumor is larger than 2 cm but not larger than 5 cm and has not spread to the axillary lymph nodes
- Stage IIB describes invasive breast cancer in which:
- the tumor is larger than 2 cm but no larger than 5 cm and has spread to the axillary lymph nodes
- OR the tumor is larger than 5 cm but has not spread to the axillary lymph nodes
- Stage III
- Stage III is divided into subcategories known as IIIA, IIIB, and IIIC
- Stage IIIA describes invasive breast cancer in which either:
- no tumor is found, but cancer is found in axillary (armpit) lymph nodes, which are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone
- OR the cancer is any size and has spread to axillary lymph nodes, which are clumped together or sticking to other structures
- Stage IIIB describes invasive breast cancer in which:
- the cancer may be any size and has spread to the chest wall and/or skin of the breast AND
- may have spread to axillary lymph nodes, which are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone
- inflammatory breast cancer is considered at least stage IIIB
- typical features of inflammatory breast cancer include: reddening of a large portion of the breast skin the breast feels warm and may be swollen cancer cells have spread to the lymph nodes and may be found in the skin
- Stage IIIC describes invasive breast cancer in which:
- there may be no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast AND
- the cancer has spread to lymph nodes above or below the collarbone AND
- the cancer may have spread to axillary lymph nodes or to lymph nodes near the breastbone
- Stage IV
- Stage IV describes invasive breast cancer that has spread beyond the breast and nearby lymph nodes to other organs of the body, such as the lungs, distant lymph nodes, skin, bones, liver, or brain
Reference:
- 1) Edge SB, Byrd DR, Compton CC, Fritz AG, Greene FL, Trotti A, editors. AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer; 2010.