If you are diagnosed with breast cancer, your doctor will discuss the stage of your cancer, which tells you whether the cancer is limited to one area of the breast or if it has spread to healthy tissues inside the breast and other parts of your body.
There are five stages of breast cancer, from stage 0 through stage 4. The lower the number, the higher the cure rate. Each stage has its own treatment options.
The stage of your cancer is based on:
- The size of the cancer
- Whether the cancer is invasive or noninvasive
- Whether the cancer spread to the lymph nodes
- Whether the cancer has spread to other parts of the body beyond your breast
The stage of your cancer will determine the best treatment.
Stage 0 breast cancer is considered non-invasive (“in situ”), meaning the cancer is still confined within breast ducts or lobules and has not yet spread to surrounding tissues. Stage 0 cancer is classified as either:
- Ductal Carcinoma In Situ (DCIS): These are cancer cells in the lining of a duct that have not invaded the surrounding breast tissue.
- Lobular Carcinoma In Situ (LCIS): These are cancer cells in the lobules of the breast. LCIS rarely develops into invasive breast cancer, but having it in one breast increases the risk of developing cancer in the other breast.
Treatment options for DCIS include:
- Breast-conserving surgery without radiation therapy
- Breast-conserving surgery and radiation therapy (followed by hormone-blocking therapy for women with hormone-sensitive cancer)
- Total mastectomy (followed by hormone-blocking therapy for women with hormone-sensitive cancer)
Treatment options for LCIS include:
- Regular exams and mammograms to monitor any potential changes (referred to as observation treatment)
- Hormone-blocking therapy to prevent development of breast cancer (for women with hormone-sensitive cancer)
- Mastectomy of both breasts, which is rarely recommended
Stage I and II (early-stage invasive)
In stage I, cancer cells have not spread beyond the breast and the tumor is no more than 2 cm across.
Stage II cancer is classified as either stage IIA or stage IIB.
In stage IIA cancer, the tumor is either:
- No more than 2 cm and has spread to the underarm lymph nodes
- Between 2-5 cm and has not spread to the underarm lymph nodes
In stage IIB cancer the tumor is either:
- Larger than 2 cm and less than 5 cm and has spread to 1-3 axillary lymph nodes
- Larger than 5 cm but has now spread to lymph nodes
Treatment options for stage I and stage II breast cancer may include:
- Breast-conserving surgery (such as lumpectomy) followed by radiation therapy
- Modified radical mastectomy with or without breast reconstruction
- Post-surgical therapy (adjuvant therapy), including radiation of lymph nodes, chemotherapy or hormone-blocking therapy
- Trastuzumab (Herceptin) given along with or following adjuvant chemotherapy for women with HER2-positive cancer
Stage III (locally advanced)
Stage III breast cancer has three different subsections: stage IIIA, stage IIIB and stage IIIC (operable or inoperable).
In stage IIIA breast cancer, the tumor is either of the following:
- Not more than 5 cm and has spread to axillary lymph nodes
- Larger than 5 cm and has spread to axillary nodes or to internal mammary nodes
Treatment options for stage IIIA breast cancer are the same as those for stages I and II.
In stage IIIB breast cancer, the tumor has spread to either of the following:
- Tissues near the breast (including the skin or chest wall)
- Lymph nodes within the breast or under the arm
Treatment options for stage IIIB may include:
- Chemotherapy and possibly hormone therapy (sometimes in combination with chemotherapy)
- Chemotherapy followed by surgery (breast-conserving surgery or total mastectomy) with lymph node dissection followed by radiation therapy and possibly more chemotherapy or hormone-blocking therapy
- Clinical trials
Stage IIIC breast cancer is classified as either operable or inoperable.
In operable stage IIIC, the cancer may be found in:
- 10 or more of the underarm lymph nodes
- Lymph nodes beneath the collarbone and near the neck on the same side of the body as the affected breast
- Lymph nodes within the breast as well as underarm lymph nodes
Treatment options for operable stage III breast cancer are the same as those for stage I and II breast cancers.
In inoperable stage III breast cancer, the cancer has spread to lymph nodes above the collarbone and near the neck on the same side of the body as the affected breast. Treatment options are the same as those for stage IIIB.
Stage IV (advanced cancer)
In stage IV, the cancer has spread (metastasized) from the breast to other parts of the body. In about 75% of cases the cancer has spread to the bone. The cancer at this stage is considered to be chronic and incurable, and the usefulness of treatments is limited.
The goals of treatment for stage IV cancer are to stabilize the disease and slow its progression, as well as to reduce pain and discomfort.
Treatment options for stage IV cancer include:
- Surgery or radiation for any localized tumors in the breast
- Chemotherapy, hormone-blocking therapy or both. Targeted therapy with trastuzumab (Herceptin), lapatinib (Tykerb) or pentuzumab (Perjeta) should be considered for women with HER2-positive cancer.
- Cancer that has spread to the brain may require radiation and high-dose steroids.
- Cancer that has spread to the bone may be helped by radiation or bisphosphonate drugs. Such treatments can relieve pain and help prevent bone fractures.
- Clinical trials of new drugs or drug combinations, or experimental treatments, such as high-dose chemotherapy with stem cell transplant