Stages of Breast Cancer

While everyone’s experience with cancer is unique, both physically and emotionally, cancer itself has certain recognizable features that doctors can identify to determine which treatments may be most effective.

A Common Language

Learn more about the language that oncologists use to define and communicate about cancer in Your Guide to Cancer Care.

Among the most important is the cancer’s stage, which is based on an assessment of the size of the primary tumor, whether it has spread, and if so, how far. Your doctors may use physical exams, lab tests, biopsies, an analysis of body fluids, and surgery in various combinations in the staging process.

The stage is indicated by a number from 0 to 4. The higher the number, the more extensive the spread of the cancer. For example, Stage 0 means that the cancer has not spread beyond the layer of cells where it developed, while Stage 4 indicates that the cancer has spread to distant organs.

Find more information about the different breast cancer stages from our partner site, Cancer Treatment Centers of America.

Learn about:

Stage 0 breast cancer

Stage 0 means that the cancer has not spread beyond the lobes or ducts of the breast where the cancer cells originated. There are two main types of non-invasive breast cancer:

Breast Cancer Surgery

Mastectomy is the surgical removal of most or all of the breast. In a lumpectomy, on the other hand, the surgeon attempts to preserve as much healthy breast tissue as possible. Learn more about breast cancer surgery.

  • Ductal carcinoma in situ, also called intraductal carcinoma or DCIS, refers to cancer cells that are confined to the lining of the breast ducts. However, if left untreated, DCIS can break through the duct and spread to nearby tissue, becoming an invasive breast cancer.

    People with DCIS may have a mastectomy or a lumpectomy followed by radiation therapy. Because the cancer has not spread at this stage, underarm lymph nodes are usually left in place. Women with DCIS may want to talk with their doctors about whether they’re a candidate for hormone therapy with anti-estrogen drugs.

  • Estrogen & Breast Cancer

    Learn about the role of estrogen in the development of breast cancer.

  • Lobular carcinoma in situ, or LCIS, refers to abnormal cells in the lining of the breast lobules. While LCIS is technically not cancer — even though it has the word “carcinoma” in its name — people with the condition have an elevated risk of developing breast cancer. The risk is increased for both breasts, even if only one of the breasts is affected with LCIS.

    Because LCIS is not in itself a life-threatening condition, most treatment is aimed at the goal of preventing invasive cancer from occurring.

Depending on their risk for developing invasive cancer, some people choose hormone therapy to try to prevent breast cancer. Others may take part in trials for promising new preventive treatments. Others may not receive any treatment, but return to the doctor for regular check-ups and screenings. Still others may have surgery to remove both breasts to try to prevent cancer from developing. Women may opt to have their breasts reconstructed at the time of the surgery, or later.

Stage I and Stage II breast cancer

Words to Know

Surgical removal of one breast is called a mastectomy, while surgical removal of both breasts is called a double mastectomy. It’s important to keep in mind, though, that while a double mastectomy can reduce the risk of developing breast cancer, it can’t eliminate it altogether. That’s because not all of the breast tissue can be removed.

Stage I and Stage II are the early stages of invasive breast cancer, which means the cancer has started to spread to nearby tissue from its site of origin. Stage I means that the cancer cells have not spread beyond the breast and the tumor isn’t larger than two centimeters, which is about three-quarters of an inch. Stage II breast cancer may be categorized as Stage IIA or Stage IIB.

Stage IIA means one of the following:

  • There is no tumor in the breast, but cancer is found in the lymph nodes under the arm.
    • Cancer in the breast is up to two centimeters across — or about three-quarters of an inch — and has also spread to nearby lymph nodes on the same side as the affected breast.
    • Cancer is located in the breast and is between two and five centimeters — the equivalent of about three-quarters of an inch to two inches. However, the cancer has not yet spread to nearby lymph nodes.

    Stage IIB indicates either of the following:

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