If you have been diagnosed with breast cancer, your doctor may recommend some tests and procedures such as a biopsy. In addition to physical examination, these tests and procedures will help your doctor determine what stage your breast cancer is in. The breast cancer stage refers to how big the tumor is and how far the cancer has spread throughout your body. Staging your breast cancer is important, because it helps your doctor know which treatment options will work best. Knowing the breast cancer stage will also help your doctor predict how your disease will behave.
TNM staging system
To stage your breast cancer, doctors use what is called the TNM staging system. T here stands for Tumor, which means your doctor will look at the following:
- tumor size
- what part of your breast is affected
- whether or not the tumor has invaded a part of your body beyond your breast, such as the muscles of your chest
- whether or not the tumor has affected your nipple or the skin of your breast.
The following are the possible T classifications:
- TX: Your tumor can’t be assessed.
- TO: There’s no clear sign or evidence of a primary tumor in the breast.
- Tis: The cancer may be any one of the following types – ductal carcinoma in situ (DCIS), lobular carcinoma in situ (LCIS), or Paget disease. “In situ” means that the tumor has not yet penetrated a layer of tissue called the basement membrane. DCIS refers to cancer cells found within the lining of ducts inside your breasts. DCIS may affect both males and females. You may have mass, pain, or nipple discharge with DCIS. In contrast, LCIS presents with no signs or symptoms. It is usually discovered due to a routine mammography. It usually affects females. Paget disease affects the nipple. It may be first seen as a reddening of the nipple, and may include the skin around it. Later on, the nipple may look as if it has an open wound that is leaking fluid.
- T1: The diameter of the tumor is 2 cm. or smaller.
- T2: The diameter of the tumor ranges from 2 to 5 cm.
- T3: The diameter of the tumor is greater than 5 cm.
- T4: The tumor has extended to the wall of the chest or the skin, regardless of its size. You may have the following symptoms: sagging of the breast; dimpling of the skin of your breast; a swollen breast; skin that has a similar texture to orange peel, ulcers or nodules on your breast.
N refers to your lymph Nodes. These small organs are a part of your body’s immune system. Each group of lymph nodes drains and filters fluid called lymph from a certain part of the body. Cancer cells from a diseased part of your body, such as the breast, may enter lymph and collect inside lymph nodes. This spread of cancer cells from the original tumor to other parts of your body, such as the lymph nodes, is called metastasis. If your lymph nodes have been affected, they may be easily felt by your doctor as enlarged, hardened lumps under your skin. Your doctor will look at the following groups of lymph nodes:
- axillary lymph nodes, which are found around your armpit
- supraclavicular and infraclavicular lymph nodes, which are found above and below your collarbone, respectively
- mammary lymph nodes, which are found around your breasts
The following are the possible N classifications:
- NX: Lymph nodes can’t be assessed.
- N0: There is no metastasis to any lymph node.
- N1: There is cancer present in the axillary lymph nodes on the same side of the body as the breast cancer. The lymph nodes are still moveable when examined.
- N2: There is cancer present in the axillary lymph nodes on the same side of the body as the breast cancer. However, the lymph nodes are no longer moveable. Rather, they are fixed. This means that they have attached themselves to each other or to other structures surrounding them. These may be blood vessels, nerves, or muscles under the arm.
- N3: There is cancer present in mammary lymph nodes, supraclavicular lymph nodes, or infraclavicular lymph nodes on the same side of the body as the breast cancer.
M refers to distant Metastasis. This refers to whether the cancer has spread to parts of the body beyond the area of the breast or the lymph nodes surrounding it. There may be metastasis to lymph nodes far away from your breast, such as those found in your neck. Breast cancer cells may also spread to your bones, or other organs such as the lungs.
- MX means that metastasis can’t be assessed.
- M0 means there is no distant metastasis.
- M1 means there is distant metastasis present.
The stages
After the tumor, lymph nodes, and presence or absence of metastasis have been assessed, your breast cancer can now be staged. Stage 0, or In Situ Breast Cancer, has a tumor classified as Tis, lymph nodes classified as N0, and no distant metastasis (M0). As mentioned above, DCIS and Paget disease may have very obvious symptoms, but LCIS may not.
Stage I breast cancer has a TNM classification of T1, N0, and M0. Stage IIA may have a tumor that is designated as T0, T1, or T2, and lymph nodes that may be N0 or N1. No distant metastasis is present in stage IIA. Stage IIB has larger tumors (T2 or T3) and lymph nodes that may be N1 or N0. Just like stage I and stage IIA, however, Stage IIB has no distant metastasis. These stages are all classified under early invasive breast cancer. You may have no symptoms, or you may be able to feel a lump in your breast if the tumor is large enough. If your lymph nodes are involved, you may also feel them as hard lumps under your arm or around your collarbone.
Stage IIIA may have tumors that range in size from T0 to T3. Lymph node involvement is N2. Stage IIIB refers to tumors that are T4, and any kind of lymph node involvement. Stage IIIC involves any size of tumor and N3 lymph nodes. All these stages do not have metastasis present.
Stage IV means distant metastasis is present, regardless of the kind of tumor or lymph nodes involved. Your symptoms will depend on which part the cancer has spread to. You may have symptoms such as bone pain if there is metastasis to your bone.