Numerical Stages of Breast Cancer

The stage of a breast cancer describes its size and the extent to w Breast Cancer Stages - Staging Information | Breast Cancer Symptoms and Diagnosis | Imaginis - The Women's Health & Wellness Resource Network

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Breast Cancer Stages - Staging Information

Numerical Stages of Breast Cancer

The stage of a breast cancer describes its size and the extent to which it has spread. The staging system ranges from Stage 0 to Stage IV.

Staging Breast Cancer
Stage Tumor Size Lymph Node Involvement Metastasis (Spread)
I Less than 2 cm No No
II Between 2-5 cm No or in same side of breast No
III More than 5 cm Yes, on same side of breast No
IV Not applicable Not applicable Yes

Stage 0 or "in situ," Tis, N0, M0: The term "in situ" literally means "in place." Stage 0 cancer is a contained cancer that has not spread beyond the breast ductal system. Fifteen to twenty percent of breast cancers detected by clinical examinations or testing are in Stage 0 (the earliest form of breast cancer). Two types of Stage 0 cancer are lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS).

  • LCIS: indicates high risk for breast cancer. Many physicians do not classify LCIS as a malignancy and often encounter LCIS serendipitously (by chance) on breast biopsy while investigating another area of concern. While the microscopic features of LCIS are abnormal and are similar to malignancy, LCIS does not behave as a cancer (and therefore is not treated as a cancer). LCIS is merely a marker for a significantly increased risk of cancer anywhere in the breast. However, bilateral simple mastectomy may be occasionally performed if LCIS patients have a strong family history of breast cancer. More likely, LCIS patients are closely monitored with physician performed clinical breast exams every four months in addition to yearly mammography. Some patients may be given the drug tamoxifen to help prevent the development of breast cancer.
  • DCIS: the cancer cells are confined to milk ducts in the breast and have not spread into the fatty breast tissue or to any other part of the body (such as the lymph nodes). DCIS may be detected on mammogram as tiny specks of calcium (known as microcalcifications) 80% of the time. Less commonly DCIS can present itself as a mass with calcifications (15% of the time); and even less likely as a mass without calcifications (less than 5% of the time). Breast biopsy is used to confirm DCIS. Standard DCIS treatment is breast-conserving therapy (BCT): lumpectomy followed by radiation treatment or mastectomy. To date, DCIS patients have chosen equally among lumpectomy and mastectomy as their treatment option, though specific cases may sometimes favor lumpectomy over mastectomy or vice versa. Click here for more information on how to treat DCIS.

Stage I ,T1, N0, M0: The primary (original) cancer is 2 cm (approximately 4/5 inch) or less in diameter and has not spread to the lymph nodes. Stage I breast cancer treatment usually consists of:


Stage IIA: T0, N1, M0 / T1, N1, M0 / T2, N0, M0: No tumor is found in the breast but it is in 1 to 3 underarm lymph nodes, or the tumor is less than 2 cm and has spread to 1 to 3 underarm lymph nodes or found by sentinel node biopsy as microscopic disease in internal mammary nodes but not on imaging studies or by clinical exam, or the tumor is larger than 2 cm in diameter and less than 5 cm but hasn't spread to underarm nodes. The cancer has not spread to distant sites.

Stage IIB: T2, N1, M0 / T3, N0, M0: The tumor is larger than 2 cm in diameter and less than 5 cm and has spread to 1 to 3 undearm lymph nodes or found by sentinel node biopsy as microscopic disease in internal mammary nodesor the tumor is larger than 5 cm and does not grow into the chest wall and has not spread to lymph nodes. The cancer has not spread to distant sites.

Common treatment for Stage II breast cancer is usually the same as Stage I treatment (lumpectomy and axillary node dissection or modified radical mastectomy), though radiation therapy is often necessary if the tumor is large or has already spread to the lymph nodes.

Stage IIIA: T0-2, N2, M0 / T3, N1-2, M0: The tumor is smaller than 5 cm in diameter and has spread to 4 to 9 undearm lymph nodes or found by imaging studies or clinical exam to have spread to internal mammary nodes, or the tumor is larger than 5 cm and has spread to 1 to 9 axillary nodes or to internal mammary nodes. The cancer hasn't spread to distant sites.

Standard Stage IIIA breast cancer treatment is modified radical mastectomy with or without breast reconstruction. Lumpectomy may be performed if the tumor may be cut free with one incision. Radiation and systemic therapy such as chemotherapy or hormonal therapy often follows surgery. If the tumor is large, neoadjuvant chemotherapy (combination of anticancer drugs administered prior to surgery to shrink the size of a tumor) may be provided, with or without hormonal therapy.

Stage IIIB: T4, N0-2, M0: The tumor grown into the chest wall or skin and may have spread to no lymph nodes or as many as 9 underarm nodes. It may or may not have spread to internal mammary nodes. The cancer has not spread to distant sites.

Stage IIIB treatment often begins with neoadjuvant chemotherapy to reduce the tumor’s size. Lumpectomy or modified radical mastectomy followed by chemotherapy, radiation, or chemotherapy plus hormonal therapy are standard treatments.

Stage IV: The primary cancer has spread out of the breast to other parts of the body (such as bone, lung, liver, brain). The treatment of Stage IV breast cancer focuses on extending survival time and relieving symptoms. Systemic treatment (treatment that affects the entire body) such as chemotherapy, hormonal therapy or both is often recommended. Radical mastectomy or the use of the drug tamoxifen may provide symptom relief in some cases.

Source: American Cancer Society

Stage Tumor (T) Node (N) Metastasis (M)
Stage 0 Tis N0 M0
Stage 1 T1 N0 M0
Stage IIA T0 N1 M0
T1 N1 M0
T2 N0 M0
Stage IIB T2 N1 M0
T3 N0 M0
Stage IIIA T0 N2 M0
T1 N2 M0
T2 N2 M0
T3 N1, N2 M0
Stage IIIB T4 any N M0
any T N3 M0
Stage IV any T any N M1

Source: American Joint Commission on Cancer and International Union Against Cancer