You will have a lot to learn and many decisions to make if you’re diagnosed with breast cancer.

Don’t get lost in unfamiliar breast cancer jargon; instead, use this glossary as your reference guide for breast cancer facts and information.

Breast Cancer Terms


Cancer that forms in the glandular tissue that lines certain internal organs and makes and releases substances in the body, such as mucus, digestive juices, or other fluids. Most cancers of the breast, pancreas, lung, prostate, colon, esophagus, and stomach are adenocarcinomas.

Adjuvant Therapy

Adjuvant therapy is treatment given in addition to your breast surgery. It’s used to kill any cancer cells that may be left in your breast or the rest of your body. It’s also sometimes given before surgery to help make the procedure easier to do. Adjuvant therapy lowers the chance of having your breast cancer come back. Your doctor will decide which therapy is right for you. Adjuvant therapy could be 1 or more of the following:

  • Chemotherapy kills cancer cells by stopping the cells’ ability to multiply. Your chemotherapy may last 3 to 6 months or longer.
  • Hormonal therapy uses medications to stop your body from making some hormones or change the way these hormones affect the body. Hormonal therapy may be taken for years.
  • Antibody therapy is when antibodies attach to growth proteins on cancer cells and kill cancer cells. Antibody therapy may be taken for up to 1 year.
  • Radiation therapy targets cancer cells that doctors can’t see but remain in the breast or lymph nodes after surgery. Radiation therapy may last 3 to 7 weeks.

(Source: Memorial Sloan Kettering Cancer Center)

Aromatase inhibitors

Newer drugs used to treat breast cancer; they reduce estrogen production and are considered a type of hormone therapy.

Aromatase inhibitors are pills. You take one pill every day.

Postmenopausal women with hormone receptor-positive breast cancer can:

  • Begin hormone therapy with an aromatase inhibitor
  • Begin hormone therapy with tamoxifen and then after a few years, switch to an aromatase inhibitor

When an aromatase inhibitor is the only hormone therapy given, it’s taken for 5-10 years.

When an aromatase inhibitor is taken after tamoxifen, the drugs are taken for a combined total of 5-10 years.

Talk with your health care provider about how long you should take an aromatase inhibitor.



Procedure that uses a needle to remove fluid from a lump.

Sometimes a small sample of breast cells or breast tissue may be taken to help make a diagnosis. This will usually be done using a core biopsy. Sometimes a fine needle aspiration (FNA) or another procedure, such as a punch biopsy, may be used. The sample is then sent to the laboratory where it is looked at under a microscope.

A mammogram or ultrasound may be used as a guide to pinpoint the area before the sample is taken, particularly when it’s very small or cannot be felt.

If you’re taking aspirin or any anticoagulants (blood-thinning tablets), let the doctor know before having a core biopsy or an FNA.

Having a core biopsy or an FNA doesn’t necessarily mean you have breast cancer.


Atypical Hyperplasia

Benign breast condition in which there are abnormalities of the breast; though not cancer, it is a risk factor for breast cancer.


Located in the armpit.


Non-cancerous; a benign tumor means there is no cancer present.

Biological therapy (immunotherapy)

A type of breast cancer treatment that boosts the body’s immune system and increases its ability to fight cancer.


Diagnostic procedure that involves removing a small sample of suspicious tissue to determine whether or not it is cancerous; a suspicious breast lump will be biopsied to look for cancer cells.


The two genes that, when mutated, are the cause of most inherited forms of breast and ovarian cancers.


Type of cancer that originates in the cells that form the lining of a gland or organ


Type of cancer treatment that involves drugs to destroy cancer cells. It’s often used in conjunction with other forms of breast cancer treatment.

Chemotherapy is the use of drugs to destroy cancer cells, usually by keeping the cancer cells from growing, dividing, and making more cells. It may be given before surgery to shrink a large tumor, make surgery easier, and/or reduce the risk of recurrence, called neoadjuvant chemotherapy. It may also be given after surgery to reduce the risk of recurrence, called adjuvant chemotherapy.

A chemotherapy regimen, or schedule, usually consists of a combination of drugs given in a specific number of cycles over a set period of time. Chemotherapy may be given on many different schedules depending on what worked best in clinical trials for that specific type of regimen. It may be given once a week, once every 2 weeks, once every 3 weeks, or even once every 4 weeks. There are many types of chemotherapy used to treat breast cancer. Common drugs include:

  • Docetaxel (Taxotere)
  • Paclitaxel (Taxol)
  • Doxorubicin (available as a generic drug)
  • Epirubicin (Ellence)
  • Pegylated liposomal doxorubicin (Doxil)
  • Capecitabine (Xeloda)
  • Carboplatin (available as a generic drug)
  • Cisplatin (available as a generic drug)
  • Cyclophosphamide (available as a generic drug)
  • Eribulin (Halaven)
  • Fluorouracil (5-FU)
  • Gemcitabine (Gemzar)
  • Ixabepilone (Ixempra)
  • Methotrexate (Rheumatrex, Trexall)
  • Protein-bound paclitaxel (Abraxane)
  • Vinorelbine (Navelbine)

A patient may receive 1 drug at a time or a combination of different drugs given at the same time. Research has shown that combinations of certain drugs are sometimes more effective than single drugs for adjuvant treatment. ASCO does not recommend routinely adding platinum chemotherapy (cisplatin or carboplatin) to anthracycline (doxorubicin or epiribicin) or taxane (paclitaxel or docetaxel) chemotherapy to treat people with inherited BRCA mutations before or after surgery.

The following drugs or combinations of drugs may be used as adjuvant therapy for early-stage and locally advanced breast cancer:

  • AC (doxorubicin and cyclophosphamide)
  • EC (epirubicin, cyclophosphamide)
  • AC or EC followed by T (paclitaxel or docetaxel), or the reverse)
  • CAF (cyclophosphamide, doxorubicin, and 5-FU)
  • CEF (cyclophosphamide, epirubicin, and 5-FU)
  • CMF (cyclophosphamide, methotrexate, and 5-FU)
  • TAC (docetaxel, doxorubicin, and cyclophosphamide)
  • TC (docetaxel and cyclophosphamide)

Therapies that target the HER2 receptor may be given with chemotherapy for HER2-positive breast cancer (see “Targeted therapy,” below). An example is the antibody trastuzumab. Combination regimens for early-stage HER2-positive breast cancer may include:

  • AC-TH (doxorubicin, cyclophosphamide, paclitaxel or docetaxel, trastuzumab)
  • AC-THP (doxorubicin, cyclophosphamide, paclitaxel or docetaxel, trastuzumab, pertuzumab)
  • TCH (paclitaxel or docetaxel, carboplatin, trastuzumab)
  • TCHP (paclitaxel or docetaxel, carboplatin, trastuzumab, pertuzumab)
  • TH (paclitaxel, trastuzumab)

The side effects of chemotherapy depend on the individual, the drug(s) used, whether the chemotherapy has been combined with other drugs, and the schedule and dose used. These side effects can include fatigue, risk of infection, nausea and vomiting, hair loss, loss of appetite, diarrhea, constipation, numbness and tingling, pain, early menopause, weight gain, and chemo-brain or cognitive dysfunction. These side effects can often be very successfully prevented or managed during treatment with supportive medications, and they usually go away after treatment is finished. For hair loss reduction, talk with your doctor about whether they do cold cap techniques. Rarely, long-term side effects may occur, such as heart damage, permanent nerve damage, or secondary cancers such as leukemia or lymphoma.

Many patients feel well during chemotherapy and are actively taking care of their families, working, and exercising during treatment, although each person’s experience can be different. Talk with your health care team about the possible side effects of your specific chemotherapy plan, and seek medical attention immediately if you experience a fever during chemotherapy.



A lump that’s made of a small, fluid-filled sac.


Tubes located in the breast that allow milk to reach the nipple for breastfeeding.

Ductal carcinoma in situ

Breast cancer that is confined to the milk ducts in the breast.


The hormone produced by the ovaries that gives women characteristics of the female sex. Estrogen is thought to encourage breast cancer cell growth.

Estrogen receptor test

A diagnostic laboratory test used to determine if a breast cancer is using estrogen to grow and if hormone therapy should be the treatment course.

Test results will give you your hormone receptor status. It will say a tumor is hormone receptor-positive if at least 1% of the cells tested have estrogen and/or progesterone receptors. Otherwise, the test will say the tumor is hormone receptor-negative.

Hormone receptor-positive (or hormone-positive) breast cancer cells have either estrogen (ER) or progesterone (PR) receptors or both. These breast cancers can be treated with hormone therapy drugs that lower estrogen levels or block estrogen receptors. Hormone receptor-positive cancers tend to grow more slowly than those that are hormone receptor-negative. Women with hormone receptor-positive cancers tend to have a better outlook in the short-term, but these cancers can sometimes come back many years after treatment.

Hormone receptor-negative (or hormone-negative) breast cancers have no estrogen or progesterone receptors. Treatment with hormone therapy drugs is not helpful for these cancers. These cancers tend to grow faster than hormone receptor-positive cancers. If they come back after treatment, it’s often in the first few years. Hormone receptor-negative cancers are more common in women who have not yet gone through menopause.

Triple-negative breast cancer cells don’t have estrogen or progesterone receptors and also don’t make any or too much of the protein called HER2. These cancers tend to be more common in women younger than 40 years of age, who are Black, or who have a mutation in the BRCA1 gene. Triple-negative breast cancers grow and spread faster than most other types of breast cancer. Because the cancer cells don’t have hormone receptors, hormone therapy is not helpful in treating these cancers. And because they don’t have too much HER2, drugs that target HER2 aren’t helpful, either. Chemotherapy can still be useful. See Triple-negative Breast Cancer to learn more.

Triple-positive cancers are ER-positive, PR-positive, and HER2-positive. These cancers can be treated with hormone drugs as well as drugs that target HER2.


Hormone therapy (hormonal therapy)

Breast cancer treatment that uses hormones to either promote or inhibit the effects of certain hormones on the cancerous tissue.

Localized cancer

Cancer confined to one area (in this case, the breast) that hasn’t spread elsewhere in the body.


Breast cancer surgery to remove the breast cancer lump and some surrounding tissue rather than the entire breast.

Lymph nodes

Small solid organs (sometimes erroneously referred to as “glands”) in the body that help to protect against foreign substances like bacteria. Breast cancer that has affected the lymph nodes may mean that the cancer has spread elsewhere in the body beyond the breast.

Magnetic resonance imaging (MRI)

Diagnostic imaging test that provides three-dimensional views of the breast and any abnormalities.


Cancerous, as in a malignant tumor.


Diagnostic screening technique using X-ray images to detect breast cancer or other abnormalities.


The surgical removal of a breast; in a double mastectomy, both breasts are removed.


The spread of cancer beyond its initial site; if breast cancer has metastasized, it has spread beyond the breasts to other parts of the body.


Calcium deposits that are too small to be felt, but can be spotted on a mammogram; some may indicate breast cancer.

Needle biopsy

Diagnostic test using a needle to draw a tissue sample, performed under the guidance of mammography or ultrasound. The sample can then be tested for cancer.


Medical professional who specializes in cancer (oncology). There are many different oncology specialists, including radiation oncologists, surgical oncologists, and medical oncologists, each focused on that particular area of cancer treatment.

Radiation therapy

Type of cancer treatment that uses high doses of radiation (X-rays).


Hormonal therapy drug that is very effective in reducing breast cancer risk.


Term used when no signs of cancer are apparent after treatment.


Breast cancer is staged from 0 to IV, according to how large a tumor is and how advanced the cancer is — if and how far it has spread throughout the body. The lower the stage, the less advanced the breast cancer.

Systemic therapy

Breast cancer treatment that affects the entire body, such as chemotherapy.


Hormonal treatment in pill form used to treat breast cancer that is sensitive to estrogen. It’s also used as a preventive therapy in women who have many risk factors for developing breast cancer.

TNM system

Classification of breast cancer based on three assessments — T for tumor size, N for lymph node involvement, and M for presence or absence of metastatic spread. The TMN classification aids in staging the cancer for making treatment decisions.


An abnormal mass that can be benign or malignant.


Diagnostic test for breast cancer that uses very high-frequency sound waves to help spot a tumor or breast abnormality. The sound waves are converted into a video or photo, which can indicate a tumor.


Brand name of the oral chemotherapy drug capecitabine, a hormonal therapy treatment for advanced breast cancer.

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