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Breast cancer is the most common type of cancer among women in the United States (other than skin cancer). After a breast cancer diagnosis, it can sometimes be hard to wrap your mind around all of the terminology used by doctors and nurses.

A tumor’s stage, grade and receptor status play important roles in determining an effective treatment plan. Below is more information on these important breast cancer terms.

Breast Cancer in Stages
Breast cancer stage indicates where the tumor is and how much is present. Early stage breast cancer ranges from Stage 0 to Stage III and, in general, the higher the number, the higher the risk of recurrence elsewhere. Recurrence means that the cancer comes back in the breast or in other parts of the body. Stage IV breast cancer is the most advanced stage of breast cancer.

• Ductal carcinoma in situ (DCIS)
  Also known as pre-invasive breast cancer, DCIS is very treatable and highly curable. In DCIS, abnormal cells are found within the duct of the breast but not outside the duct. Because DCIS is confined to the duct, it does not have the potential to spread elsewhere in the body. DCIS can recur within the breast and treatment is given to reduce that risk. DCIS is generally removed with a lumpectomy (often followed by radiation) or mastectomy and is nearly always curable. ​Learn more about DCIS.
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• Invasive breast cancer
  Invasive breast cancer indicates that the tumor has extended from the milk duct or lobule into other normal tissues of the breast. Invasive breast cancer therefore has the potential to spread elsewhere in the body. Treatments are aimed at reducing that risk, along with the risk of recurrence within the breast as well. Invasive breast cancer is categorized as stage I, II, III, or IV, depending on the amount and location of cancer in the body. Treatment plans may include surgery, radiation therapy, chemotherapy/endocrine therapy, and/or targeted biologic therapy.​

Support in Stages

Learn about specialized support resources by diagnosis. 

Early Stage

Inflammatory Breast Cancer

Metastatic Breast Cancer

Related Pages

Learn about treatment and symptom management. 

Treatment Types

Menopause and Menopausal Symptoms

Fertility 

Sexual Health 

Lymphedema 

• Inflammatory breast cancer
  Inflammatory breast cancer (IBC) is a subset of invasive breast cancer. With IBC, cancer cells block the lymph vessels of the skin of the breast, causing the breast to appear red or inflamed. Unlike other types of breast cancer, IBC generally does not present with a lump. IBC is typically diagnosed through a clinical exam, and confirmed with a breast biopsy. Prompt and accurate diagnosis and treatment is important because of the aggressive nature of the disease. The treatment starts with systemic therapy (chemotherapy and targeted therapy), followed by surgery and radiation therapy.
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  Watch an IBC informational video.
  Read Frequently Asked Questions about IBC.
  ​Learn about Dana-Farber's IBC Program.​​

• Metastatic breast cancer
  Metastatic breast cancer (MBC), or Stage IV breast cancer, has spread from the breast to other distant parts of the body. Medications are the main treatments used and are aimed at controlling the growth and spread of the cancer. Radiation and surgery are occasionally used to fix a symptom, but are not generally aimed at removing all of the cancer. 
  
  Learn more about metastatic breast cancer.
  ​Learn more about clinical trials for metastatic breast cancer.

Grade
The grade of a tumor is an indication of the likelihood that the cancer will spread. In general, low and intermediate grade tumors have a lower risk of recurrence, whereas high grade tumors are associated with a higher risk of recurrence. 

Hormone receptor status
Breast cancer cells can sometimes carry receptors for estrogen or progesterone hormones. If a tumor carries estrogen receptors, it is called estrogen receptor (ER) positive, and if it carries progesterone receptors, it is called progesterone receptor (PR) positive. The hormone receptor status of a tumor can affect a patient’s treatment plan. If a tumor is hormone-positive, therapy may include medications that block hormone signaling or reduce the body’s natural estrogen production, such as tamoxifen or medications called aromatase inhibitors. Learn more about hormone therapy.

HER2 
Like hormone receptors, the HER2 protein, also called Human Epidermal Growth Factor Receptor 2, can also be found on the surface of breast cancer cells in some cancers. If a tumor has higher than normal amounts of this protein, it may be treated with drugs that target HER2, such as trastuzumab (Herceptin), which are highly effective at reducing the risk of recurrence or controlling HER2 positive breast cancer. 
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If a tumor does not have an estrogen receptor, progesterone receptor, or HER2, it is known as triple-negative breast cancer. This type of breast cancer may be associated with a higher risk of recurrence, though many patients with TNBC are still at lower risk. Additionally, new treatments have been developed over the past years to effectively target TNBC and have dramatically changed its treatment. 
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External Resources

Breastcancer.org​ provides information about breast cancer and breast health, a blog, and discussion boards.

Cancer.net by the American Society of Clinical Oncology (ASCO) provides oncologist-approved cancer information. ​

Susan G. Komen provides up-to-date information on breast cancer risk factors, early detection, screening, diagnosis, treatment, and support.