Once a woman is diagnosed with breast cancer, her doctor will run more tests to find out whether the disease has spread from the breast to other parts of her body. The testing process is called “breast cancer staging,” and the results are given a stage designation that describes the extent of the disease. The stage helps a woman and her doctor plan the best breast cancer treatment. The stage also relates to the odds of recovery, or prognosis, because cancer that remains confined to the breast tends to be more treatable than cancer that has spread.
During breast cancer staging tests, a woman with breast cancer may have a chest X-ray to look for cancer in the lungs, and a blood test to check for cancer in the liver. Often, an abdominal CT scan or sonogram will be done to assess the liver. A more complicated test called a bone scan can detect cancer in the bones.
An estrogen-receptor test is done on a biopsied tissue sample. This test can find out whether the cancer cells are of the type that grows when exposed to hormones, usually estrogen. This condition is more common among postmenopausal women, although some premenopausal women with breast cancer fit into this category as well. Estrogen-receptor positive cancers are likely to respond well to hormone-blocking drugs, such as tamoxifen.
Here are the four numbered stages of breast cancer, as well as three more descriptive terms for special conditions:
Carcinoma in situ/Stage 0
The two conditions referred to as breast cancer in situ are defined by being confined to where they started, and by not invading neighboring tissues. Ductal carcinoma in situ (also called DCIS or intraductal carcinoma) is a very early form of breast cancer. Lobular carcinoma in situ (LCIS) is not actually cancer; it is sometimes referred to as stage 0 breast cancer because women with this condition have a 25% chance of developing breast cancer in the next 25 years. Interestingly, with LCIS you have an equal chance of developing breast cancer in either breast, regardless of which side the lesion first appeared on.
The cancer is less than 2 centimeters (about an inch) and has not spread beyond the breast.
The cancer is one of the following:
- Less than 2 inches around, but has spread to the lymph nodes in the armpit (the axillary lymph nodes)
- Between 2 and 5 centimeters (1 to 2 inches) and may or may not have spread to the axillary lymph nodes
- Larger than 5 centimeters (larger than 2 inches) but has not spread to the axillary lymph nodes
Stage III (divided into IIIA and IIIB)
Stage IIIA cancer is either:
- Smaller than 5 centimeters (less than 2 inches) and has spread to the lymph nodes under the arm, and the lymph nodes are attached to each other or to other structures
- Larger than 5 centimeters (larger than 2 inches) and has spread to the lymph nodes under the arm
Stage IIIB cancer has either:
- Spread to tissues near the breast (the skin or chest wall, including the ribs and muscles within the chest)
- Spread to lymph nodes inside the chest wall along the breast bone
Cancer has spread beyond the breast to other organs — usually the bones, lungs, liver, or brain. Or, cancer may have spread locally to the skin and lymph nodes inside the neck, near the collarbone.
Inflammatory breast cancer
This is a special, rare form of breast cancer. The breast appears inflamed (red and warm). This type of breast cancer tends to spread rapidly.
Recurrent breast cancer
Recurrent cancer is cancer that has returned (recurred) after treatment. It may come back in the breast, the chest wall, or in a completely different part of the body.