1. What is adjuvant therapy for breast cancer?

Adjuvant therapy for breast cancer is any treatment given after primary therapy to increase the chance of long-term disease-free survival. Primary therapy is the main treatment used to reduce or eliminate the cancer. Primary therapy for breast cancer usually includes surgery—a mastectomy (removal of the breast) or a lumpectomy (surgery to remove the tumor and a small amount of normal tissue around it; a type of breast-conserving surgery). During either type of surgery, one or more nearby lymph nodes are also removed to see if cancer cells have spread to the lymphatic system. When a woman has breast-conserving surgery, primary therapy almost always includes radiation therapy.

Even in early-stage breast cancer, cells may break away from the primary tumor and spread to other parts of the body (metastasize). Therefore, doctors give adjuvant therapy to kill any cancer cells that may have spread, even if they cannot be detected by imaging or laboratory tests. Studies have shown that adjuvant therapy for breast cancer may increase the chance of long-term survival by preventing a recurrence (1).

2. What types of adjuvant therapies are used for breast cancer?

Most adjuvant therapies are systemic: They use substances that travel through the bloodstream, reaching and affecting cancer cells all over the body. Adjuvant therapy for breast cancer can include chemotherapy, hormonal therapy, the targeted drug trastuzumab (Herceptin®), radiation therapy, or a combination of treatments.

• Adjuvant chemotherapy uses drugs to kill cancer cells. Research has shown that adjuvant chemotherapy for early-stage breast cancer helps to prevent the cancer from returning (1). Usually, more than one drug is given during adjuvant chemotherapy (called combination chemotherapy).
• Hormonal therapy deprives breast cancer cells of the hormone estrogen, which many breast tumors need to grow. A commonly used hormonal treatment is the drug tamoxifen, which blocks estrogen's activity in the body. Studies have shown that tamoxifen helps prevent the original cancer from returning and also helps to prevent the development of new cancers in the other breast; however, many women develop resistance to the drug over time (1, 2). Tamoxifen can be given to both premenopausal and postmenopausal women.

  Postmenopausal women may also receive hormonal therapy with a newer type of drug called an aromatase inhibitor (AI), either after tamoxifen therapy or instead of tamoxifen therapy. Rather than blocking estrogen's activity, as tamoxifen does, AIs prevent the body from making estrogen. Clinical trials suggest that AIs may be more effective than tamoxifen in preventing breast cancer recurrence in some women (3–6). Using AIs to block estrogen production in premenopausal women is not very effective, in part because the ovary is stimulated to make more estrogen when blood levels of estrogen fall below normal. This does not occur in postmenopausal women, whose ovaries have stopped making estrogen.

  Some premenopausal women may undergo ovarian ablation or suppression, which greatly reduces the amount of estrogen produced by the body, either permanently or temporarily. Premenopausal women who have BRCA1 or BRCA2 gene mutations are at very high risk of breast cancer recurrence as well as of ovarian cancer and may decide to have their ovaries surgically removed as part of adjuvant therapy. The surgical removal of the ovaries also decreases the risk of ovarian cancer. Other premenopausal women who have a lower risk of recurrence may be prescribed drugs that temporarily suppress the function of the ovaries, in addition to tamoxifen.

• Trastuzumab is a monoclonal antibody that targets cancer cells that make too much of, or overexpress, a protein called HER2. When cancer cells overexpress HER2 protein, they are said to be HER2 positive. Approximately 20 percent of all breast cancers are HER2 positive. Clinical trials have shown that targeted therapy with trastuzumab in addition to chemotherapy decreases the risk of relapse for women with HER2-positive tumors (7–9).
• Radiation therapy is usually given after breast-conserving surgery and may be given after a mastectomy. (When doctors give radiation therapy after breast-conserving surgery, it is usually considered part of primary therapy.) For women at high risk of recurrence, doctors may use radiation therapy after mastectomy to kill cancer cells that may be left in tissues next to the breast, such as the chest wall or nearby lymph nodes. Radiation therapy is a type of local therapy, not systemic therapy.

3. How is adjuvant therapy given, and for how long?

Adjuvant chemotherapy is given orally (by mouth) or by injection into a blood vessel. It is given in cycles, consisting of a treatment period followed by a recovery period. The number of cycles depends on the types of drugs used. Most patients do not have to stay in the hospital for chemotherapy—they can be treated as an outpatient or at the doctor’s office. Adjuvant chemotherapy usually does not last for much more than 6 months.

Hormonal therapy is usually given orally, as a pill.

• Most women who undergo hormonal therapy take tamoxifen every day for 5 years.
• Some women may take an aromatase inhibitor every day for 5 years instead of tamoxifen.
• Some women may receive additional treatment with an aromatase inhibitor after 5 years of tamoxifen.
• Finally, some women may switch to taking an aromatase inhibitor after 2 or 3 years of tamoxifen, for a total of 5 or more years of hormonal therapy.

Trastuzumab is given by infusion into a blood vessel every 1 to 3 weeks for a year.

Radiation therapy given after mastectomy is divided into small doses given once a day over the course of several weeks. Radiation therapy may not be given at the same time as some types of chemotherapy or hormonal therapy.

4. How do doctors decide who needs adjuvant therapy?

Not all women with breast cancer need adjuvant therapy. Patients at higher risk of cancer recurrence are more likely to need adjuvant therapy. Doctors look at both prognostic and predictive factors to decide which patients might benefit from adjuvant treatments. Prognostic factors help doctors estimate how likely a tumor is to recur. Predictive factors help doctors estimate how likely cancer cells are to respond to a particular treatment.

In addition to a woman’s age and menopausal status, several other prognostic factors are used to determine the risk of recurrence (10).

• Stage of the cancer: Cancer stage refers to the size of the tumor and whether it is in the breast only or has spread to nearby lymph nodes or other places in the body. Larger tumors (especially those that are more than 5 centimeters—about 2 inches—in diameter) are more likely to recur than small tumors. Breast cancer often first spreads to the lymph nodes under the arm (axillary lymph nodes). During surgery, doctors usually remove some of these underarm lymph nodes to determine whether they contain cancer cells. Cancer that has spread to these lymph nodes is more likely to recur.
• Tumor grade: This term refers to how closely the tumor cells resemble normal breast cells when viewed under a microscope. Tumors with cells that bear little or no resemblance to normal breast cells (called poorly differentiated tumors) are more likely to recur. Women with tumor cells that look like normal breast cells (called well-differentiated tumors) tend to have a better prognosis.
• Proliferative capacity of the tumor: Proliferative capacity refers to how fast the tumor cells divide, or multiply, to form more cells. Women who have tumor cells that have a low proliferative capacity (that is, the cells divide less often and grow more slowly) tend to have a better prognosis.
• Hormone receptor status: The cells of many breast tumors express receptors for the hormones estrogen and progesterone. Tumors with cells that do not express hormone receptors are more likely to recur. Doctors can determine whether a tumor expresses hormone receptors with laboratory tests.
• HER2 status: Tumors that produce too much of a protein called HER2 are more likely to recur. Doctors can determine whether a tumor produces too much HER2 with a laboratory test.

Two major predictive factors are currently used to determine whether cancer cells might respond to particular treatments (11):

• Hormone receptor status: As mentioned above, the cells of many breast tumors express receptors for the hormones estrogen and progesterone. These hormones bind to the receptors and help the cancer cells grow. Blocking the activity of these hormones with hormonal therapy stops the growth of the cancer cells. Hormonal therapy will not help patients whose tumors do not express hormone receptors.
• HER2 status: Tumors that produce too much of the protein HER2 can be treated with trastuzumab, which can cut the risk of recurrence by up to about half (7). Women whose tumors do not produce too much HER2 do not benefit from treatment with trastuzumab.

Clinical trials are under way to see if genetic information collected from tumors can help predict which women will benefit from adjuvant chemotherapy. See Question 7 for more information about these tests.

Prognostic and predictive factors cannot determine exactly which patients may benefit from adjuvant therapy and which patients may benefit from primary therapy alone. Decisions about adjuvant therapy must be made on an individual basis. This complicated decision-making process is best carried out by consulting an oncologist, a doctor who specializes in cancer treatment. In addition to the factors described above, doctors will take into account a woman's general health and her personal treatment preferences.

5. What is neoadjuvant therapy?

Neoadjuvant therapy is treatment given before primary therapy. A woman may receive neoadjuvant chemotherapy for breast cancer to shrink a tumor that is inoperable in its current state, so it can be surgically removed. A woman whose tumor can be removed by mastectomy may instead receive neoadjuvant therapy to shrink the tumor enough to allow breast-conserving surgery (12–14).

Neoadjuvant chemotherapy is given in the same manner as adjuvant chemotherapy (see Question 3). If a tumor does not respond (shrink) or continues to grow during neoadjuvant chemotherapy, the doctor may stop treatment and try another type of chemotherapy or perform surgery instead, depending on the stage of the cancer.

Clinical trials are examining whether hormonal therapy or trastuzumab is effective when given before surgery. See Question 7 for more information about clinical trials of neoadjuvant therapies.

6. What are the side effects of adjuvant and neoadjuvant therapy?

Chemotherapy: The side effects of chemotherapy depend mainly on the drugs a woman receives. As with other types of treatment, side effects vary from person to person. In general, anticancer drugs affect rapidly dividing cells. These include blood cells, which fight infection, cause the blood to clot, and carry oxygen to all parts of the body. When blood cells are affected by anticancer drugs, patients are more likely to get infections and bruise or bleed easily, and may have less energy during treatment and for some time afterward. Cells in hair follicles and cells that line the digestive tract also divide rapidly. As a result of chemotherapy, patients may lose their hair and may have other side effects, such as loss of appetite, nausea, vomiting, diarrhea, or mouth sores.

Doctors can prescribe medications to help control nausea and vomiting caused by chemotherapy. They also monitor patients for any signs of other problems and may adjust the dose or schedule of treatment if problems arise. In addition, doctors advise women who have a lowered resistance to infection because of low blood cell counts to avoid crowds and people who are sick or have colds. The side effects of chemotherapy are generally short-term. They gradually go away during the recovery part of the chemotherapy cycle or after the treatment is over. However, some chemotherapy drugs, called anthracyclines, can increase the risk of heart problems. Women who receive an anthracycline as part of their treatment should be monitored closely by their doctors for heart problems for the rest of their lives.

Hormonal therapy: In general, the side effects of tamoxifen are similar to some of the symptoms of menopause. The most common side effects are hot flashes, vaginal discharge, and nausea. Tamoxifen also increases the risk of cataract development. Not all women who take tamoxifen have these symptoms. Most of these side effects do not require medical attention.

Doctors carefully monitor women taking tamoxifen for any signs of more serious side effects. Among women who have not had a hysterectomy (surgery to remove the uterus), the risk of developing uterine cancer is increased for those taking tamoxifen. Women who take tamoxifen should talk with their doctor about having regular pelvic exams, and should be examined promptly if they have pelvic pain or any abnormal vaginal bleeding. Women taking tamoxifen, particularly those who are receiving chemotherapy along with tamoxifen, have a greater risk of developing a blood clot.

Aromatase inhibitors also cause hot flashes, vaginal dryness, and other symptoms of menopause. Women taking an aromatase inhibitor may also experience joint pain (arthralgia) or muscle pain (myalgia) during treatment.

Women taking aromatase inhibitors may have a higher risk of heart problems than those taking tamoxifen. Aromatase inhibitors also reduce bone density and increase the risk of bone fractures. Doctors should carefully monitor women taking aromatase inhibitors for any signs of heart damage or changes in bone density. A type of drug called a bisphosphonate can help reduce bone loss caused by aromatase inhibitors for patients at high risk of fractures.

Trastuzumab: Side effects from trastuzumab can include nausea, vomiting, hot flashes, and joint pain. Trastuzumab can also increase the risk of heart problems. Women receiving trastuzumab should be monitored closely by their doctors for any reduction in the heart’s ability to pump blood, both during and after treatment.

Radiation therapy: Skin in the area treated by radiation may become red, dry, tender, and itchy, and the breast may feel heavy and tight. These problems usually go away over time. Women receiving radiation therapy may become very tired, especially in the later weeks of treatment.

Careful studies have shown that the risks of adjuvant therapy for breast cancer are outweighed by the benefit of treatment—that is, increasing the chance of long-term survival. However, it is important for women to share any concerns they may have about their treatment or side effects with their doctor or other health care provider.

7. What are doctors and scientists doing to learn more about adjuvant and neoadjuvant therapy for breast cancer?

Doctors and scientists are conducting research studies called clinical trials to learn how to treat breast cancer more effectively. In these studies, researchers compare two or more groups of patients who receive different treatments. Clinical trials allow researchers to examine the effectiveness of new treatments in comparison with standard ones, as well as to compare the side effects of the treatments.

Researchers are also investigating whether molecular information obtained from a woman’s tumor can be used to decide if the woman would benefit from adjuvant therapy. Two large clinical trials sponsored by the National Cancer Institute (NCI), a part of the National Institutes of Health, are currently under way in this area of research.

The Trial Assigning Individualized Options for Treatment (TAILORx) is examining whether molecular markers that are frequently associated with risk of recurrence among women who have early-stage breast cancer can be used to assign patients to the most appropriate and effective treatment. TAILORx is using a test called Oncotype DX™, which calculates the risk of recurrence based on the levels of expression of 21 genes in breast tumors, in over 10,000 women recruited at 900 sites in the United States and Canada. Based on their risk of recurrence, women will be assigned to one of three different treatment groups: Women with a high risk of recurrence will receive chemotherapy plus hormonal therapy; women with a low risk of recurrence will receive hormonal therapy alone; and women with an intermediate risk of recurrence will be randomly assigned to receive adjuvant hormonal therapy, with or without chemotherapy. Because the degree of benefit of chemotherapy for women with an intermediate risk of recurrence is unknown, TAILORx seeks to determine whether the Oncotype DX test will be helpful in future treatment planning for this group.

In the Microarray In Node-negative Disease may Avoid Chemotherapy Trial (MINDACT), investigators are studying genomic profiling compared with clinical assessment to determine the need for chemotherapy in women with node-negative breast cancer (cancer that has not spread to the axillary lymph nodes). The investigators will use both a 70-gene signature test and clinical assessment to determine the women’s risk of recurrence. Women eligible to receive chemotherapy who have a high risk of recurrence according to the clinical criteria and a low risk of recurrence according to the 70-gene signature, or have a low risk of recurrence according to the clinical criteria and a high risk of recurrence according to the 70-gene signature, will be randomly assigned to receive treatment based on either the genetic or clinical criteria to determine which better predicts the need for chemotherapy.

Women with breast cancer who are interested in taking part in a clinical trial should talk with their doctor. Complete listings of current clinical trials testing adjuvant and neoadjuvant therapies for female breast cancer are available from NCI’s Web site:

• Trials of adjuvant therapy for female breast cancer ¹
• Trials of neoadjuvant therapy for female breast cancer ²

Additional information about clinical trials can be found on NCI's Web site at http://www.cancer.gov/clinicaltrials on the Internet. NCI's Cancer Information Service (CIS) can also provide information about clinical trials and help with clinical trial searches. Call the CIS at 1–800–4–CANCER (1–800–422–6237).

Selected References

1. Early Breast Cancer Trialists’ Collaborative Group (EBCTCG). Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: An overview of the randomised trials. Lancet 2005; 365(9472):1687–1717.
2. Colleoni M, Gelber S, Goldhirsch A, et al. Tamoxifen after adjuvant chemotherapy for premenopausal women with lymph node-positive breast cancer: International Breast Cancer Study Group Trial 13–93. Journal of Clinical Oncology 2006; 24(9):1332–1341.
   

3. Coates AS, Keshaviah A, Thürlimann B, et al. Five years of letrozole compared with tamoxifen as initial adjuvant therapy for postmenopausal women with endocrine-responsive early breast cancer: Update of study BIG 1–98. Journal of Clinical Oncology 2007; 25(5):486–492.
   

4. The Arimidex, Tamoxifen, Alone or in Combination (ATAC) Trialists’ Group. Effect of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: 100-month analysis of the ATAC Trial. Lancet Oncology 2008; 9(1):45–53.
   

5. Coombes RC, Kilburn LS, Snowdon CF, et al. Survival and safety of exemestane versus tamoxifen after 2–3 years’ tamoxifen treatment (Intergroup Exemestane Study): A randomised controlled trial. Lancet 2007; 369(9561):559–570.
   

6. Boccardo F, Rubagotti A, Guglielmini P, et al. Switching to anastrozole versus continued tamoxifen treatment of early breast cancer. Updated results of the Italian Tamoxifen Anastrozole (ITA) Trial. Annals of Oncology 2006; 17(Suppl 7):vii10–vii14.
   

7. Piccart-Gebhart MJ, Procter M, Leyland-Jones B, et al. Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer. New England Journal of Medicine 2005; 353(16):1659–1672.
   

8. Smith I, Procter M, Gelber RD, et al. 2-year follow-up of trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer: A randomised controlled trial. Lancet 2007; 369(9555):29–36.
   

9. Romond EH, Perez EA, Bryant J, et al. Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer. New England Journal of Medicine 2005; 353(16):1673–1684.
   

10. Goldhirsch A, Glick JH, Gelber RD, et al. Meeting highlights: International expert consensus on the primary therapy of early breast cancer 2005. Annals of Oncology 2005; 16(10):1569–1583.
    

11. Lonning PE. Breast cancer prognostication and prediction: Are we making progress? Annals of Oncology 2007; 18(Suppl 8):viii3–7.
    

12. Fisher B, Bryant J, Wolmark N, et al. Effect of preoperative chemotherapy on the outcome of women with operable breast cancer. Journal of Clinical Oncology 1998; 16(8):2672–2685.
    

13. van der Hage JA, van de Velde CJ, Julien JP, et al. Preoperative chemotherapy in primary operable breast cancer: Results from the European Organization for Research and Treatment of Cancer Trial 10902. Journal of Clinical Oncology 2001; 19(22):4224–4237.
    

14. Mauri D, Pavlidis N, Ioannidis JP. Neoadjuvant versus adjuvant systemic treatment in breast cancer: A meta-analysis. Journal of the National Cancer Institute 2005; 97(3):188–194.
    

# # #

• National Cancer Institute Fact Sheet 7.16, Tamoxifen: Questions and Answers ³
  (http://www.cancer.gov/cancertopics/factsheet/Therapy/tamoxifen)
• National Cancer Institute Fact Sheet 7.45, Herceptin® (Trastuzumab): Questions and Answers ⁴
  (http://www.cancer.gov/cancertopics/factsheet/therapy/herceptin)
• Chemotherapy and You: Support for People With Cancer ⁵
  (http://www.cancer.gov/cancertopics/chemotherapy-and-you)
• Radiation Therapy and You: Support for People With Cancer ⁶
  (http://www.cancer.gov/cancertopics/radiation-therapy-and-you)
• Taking Part in Cancer Treatment Research Studies ⁷
  (http://www.cancer.gov/clinicaltrials/Taking-Part-in-Cancer-Treatment-Research-Studies)
• Breast Cancer Home Page ⁸
  (http://www.cancer.gov/cancertopics/types/breast)
• Clinical Trials Home Page ⁹
  (http://www.cancer.gov/clinicaltrials)

How can we help?

We offer comprehensive research-based information for patients and their families, health professionals, cancer researchers, advocates, and the public.

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Glossary Terms

Additional cancer treatment given after the primary treatment to lower the risk that the cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, targeted therapy, or biological therapy.

A type of antibiotic that comes from certain types of Streptomyces bacteria. Anthracyclines are used to treat many types of cancer. Anthracyclines damage the DNA in cancer cells, causing them to die. Daunorubicin, doxorubicin, and epirubicin are anthracyclines.

A drug that prevents the formation of estradiol, a female hormone, by interfering with an aromatase enzyme. Aromatase inhibitors are used as a type of hormone therapy for postmenopausal women who have hormone-dependent breast cancer.

Joint pain.

In healthcare, a process used to learn about a patient’s condition. This may include a complete medical history, medical tests, a physical exam, a test of learning skills, tests to find out if the patient is able to carry out the tasks of daily living, a mental health evaluation, and a review of social support and community resources available to the patient.

A lymph node in the armpit region that drains lymph from the breast and nearby areas.

A drug or substance used to treat hypercalcemia (abnormally high blood calcium) and bone pain caused by some types of cancer. Forms of bisphosphonates are also used to treat osteoporosis and for bone imaging. Bisphosphonates inhibit a type of bone cell that breaks down bone. Also called diphosphonate.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called CBC and complete blood count.

A mass of blood that forms when blood platelets, proteins, and cells stick together. When a blood clot is attached to the wall of a blood vessel, it is called a thrombus. When it moves through the bloodstream and blocks the flow of blood in another part of the body, it is called an embolus.

A tube through which the blood circulates in the body. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins.

A measure of the amount of minerals (mostly calcium and phosphorous) contained in a certain volume of bone. Bone density measurements are used to diagnose osteoporosis (a condition marked by decreased bone mass), to see how well osteoporosis treatments are working, and to predict how likely the bones are to break. Low bone density can occur in patients treated for cancer. Also called BMD, bone mass, and bone mineral density.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

An operation to remove the breast cancer but not the breast itself. Types of breast-conserving surgery include lumpectomy (removal of the lump), quadrantectomy (removal of one quarter, or quadrant, of the breast), and segmental mastectomy (removal of the cancer as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor). Also called breast-sparing surgery.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

The Cancer Information Service is the National Cancer Institute's link to the public, interpreting and explaining research findings in a clear and understandable manner, and providing personalized responses to specific questions about cancer. Access the CIS by calling 1-800-4-CANCER (1-800-422-6237), or by using the LiveHelp instant-messaging service at https://cissecure.nci.nih.gov/livehelp/welcome.asp. Also called CIS.

A condition in which the lens of the eye becomes cloudy. Symptoms include blurred, cloudy, or double vision; sensitivity to light; and difficulty seeing at night. Without treatment, cataracts can cause blindness. There are many different types and causes of cataracts. They may occur in people of all ages, but are most common in the elderly.

A measure of length in the metric system. There are 100 centimeters in a meter and 2½ centimeters in an inch.

Treatment with drugs that kill cancer cells.

The muscles, bones, and joints that make up the area of the body between the neck and the abdomen.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

Frequent and watery bowel movements.

The organs through which food and liquids pass when they are swallowed, digested, and eliminated. These organs are the mouth, esophagus, stomach, small and large intestines, and rectum and anus.

The length of time after treatment for a specific disease during which a patient survives with no sign of the disease. Disease-free survival may be used in a clinical study or trial to help measure how well a new treatment works.

The amount of medicine taken, or radiation given, at one time.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

Breast cancer that has not spread beyond the breast or the axillary lymph nodes. This includes ductal carcinoma in situ and stage I, stage IIA, stage IIB, and stage IIIA breast cancers.

A type of hormone made by the body that helps develop and maintain female sex characteristics and the growth of long bones. Estrogens can also be made in the laboratory. They may be used as a type of birth control and to treat symptoms of menopause, menstrual disorders, osteoporosis, and other conditions.

A description of a tumor based on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.

A shaft or opening on the surface of the skin through which hair grows.

A protein involved in normal cell growth. It is found on some types of cancer cells, including breast and ovarian. Cancer cells removed from the body may be tested for the presence of HER2/neu to help decide the best type of treatment. HER2/neu is a type of receptor tyrosine kinase. Also called c-erbB-2, human EGF receptor 2, and human epidermal growth factor receptor 2.

A monoclonal antibody that binds to HER2 (human epidermal growth factor receptor 2), and can kill HER2-positive cancer cells. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Herceptin is used to treat breast cancer that is HER2-positive and has spread after treatment with other drugs. It is also used with other anticancer drugs to treat HER2-positive breast cancer after surgery. Herceptin is also being studied in the treatment of other types of cancer. Also called trastuzumab.

Treatment that adds, blocks, or removes hormones. For certain conditions (such as diabetes or menopause), hormones are given to adjust low hormone levels. To slow or stop the growth of certain cancers (such as prostate and breast cancer), synthetic hormones or other drugs may be given to block the body’s natural hormones. Sometimes surgery is needed to remove the gland that makes a certain hormone. Also called endocrine therapy, hormone therapy, and hormone treatment.

A cell protein that binds a specific hormone. The hormone receptor may be on the surface of the cell or inside the cell. Many changes take place in a cell after a hormone binds to its receptor.

A sudden, temporary onset of body warmth, flushing, and sweating (often associated with menopause).

Surgery to remove the uterus and, sometimes, the cervix. When the uterus and the cervix are removed, it is called a total hysterectomy. When only the uterus is removed, it is called a partial hysterectomy.

In medicine, a process that makes pictures of areas inside the body. Imaging uses methods such as x-rays (high-energy radiation), ultrasound (high-energy sound waves), and radio waves.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

Describes a condition that cannot be treated by surgery.

A medical procedure that involves testing a sample of blood, urine, or other substance from the body. Tests can help determine a diagnosis, plan treatment, check to see if treatment is working, or monitor the disease over time.

Treatment that affects cells in the tumor and the area close to it.

Surgery to remove abnormal tissue or cancer from the breast and a small amount of normal tissue around it. It is a type of breast-sparing surgery.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.

Surgery to remove the breast (or as much of the breast tissue as possible).

The time of life when a woman’s ovaries stop working and menstrual periods stop. Natural menopause usually occurs around age 50. A woman is said to be in menopause when she hasn’t had a period for 12 months in a row. Symptoms of menopause include hot flashes, mood swings, night sweats, vaginal dryness, trouble concentrating, and infertility.

To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic tumor are like those in the original (primary) tumor.

An instrument that is used to look at cells and other small objects that cannot be seen with the eye alone.

In medicine, to regularly watch and check a person or condition to see if there is any change. Also refers to a device that records and/or displays patient data, such as for an electrocardiogram (EKG).

A type of protein made in the laboratory that can locate and bind to substances in the body, including tumor cells. There are many kinds of monoclonal antibodies. Each monoclonal antibody is made to find one substance. Monoclonal antibodies are being used to treat some types of cancer and are being studied in the treatment of other types. They can be used alone or to carry drugs, toxins, or radioactive materials directly to a tumor.

Pain in a muscle or group of muscles.

A federal agency in the U.S. that conducts biomedical research in its own laboratories; supports the research of non-Federal scientists in universities, medical schools, hospitals, and research institutions throughout the country and abroad; helps in the training of research investigators; and fosters communication of medical information. Access the National Institutes of Health Web site at http://www.nih.gov. Also called NIH.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

NCI, part of the National Institutes of Health of the United States Department of Health and Human Services, is the Federal Government's principal agency for cancer research. It conducts, coordinates, and funds cancer research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer. Access the NCI Web site at http://www.cancer.gov. Also called National Cancer Institute.

Treatment given as a first step to shrink a tumor before the main treatment, which is usually surgery, is given. Examples of neoadjuvant therapy include chemotherapy, radiation therapy, and hormone therapy. It is a type of induction therapy.

Cancer that has not spread to the lymph nodes.

A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.

A patient who visits a health care facility for diagnosis or treatment without spending the night. Sometimes called a day patient.

Surgery, radiation therapy, or a drug treatment to stop the functioning of the ovaries. Also called ovarian suppression.

Cancer that forms in tissues of the ovary (one of a pair of female reproductive glands in which the ova, or eggs, are formed). Most ovarian cancers are either ovarian epithelial carcinomas (cancer that begins in the cells on the surface of the ovary) or malignant germ cell tumors (cancer that begins in egg cells).

One of a pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus.

In biology, to make too many copies of a protein or other substance. Overexpression of certain proteins or other substances may play a role in cancer development.

A colorless, odorless gas. It is needed for animal and plant life. Oxygen that is breathed in enters the blood from the lungs and travels to the tissues.

A physical examination in which the health care professional will feel for lumps or changes in the shape of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum. The health care professional will also use a speculum to open the vagina to look at the cervix and take samples for a Pap test. Also called internal examination.

Having to do with the time after menopause. Menopause (“change of life”) is the time in a woman's life when menstrual periods stop permanently.

Having to do with the time before menopause. Menopause ("change of life") is the time of life when a woman's menstrual periods stop permanently.

A doctor's order for medicine or another intervention.

A type of hormone made by the body that plays a role in the menstrual cycle and pregnancy. Progesterone can also be made in the laboratory. It may be used as a type of birth control and to treat menstrual disorders, infertility, symptoms of menopause, and other conditions.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific physiologic effect in the cell.

Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. The cancer may come back to the same place as the original (primary) tumor or to another place in the body. Also called recurrent cancer.

The return of signs and symptoms of cancer after a period of improvement.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

Affecting the entire body.

Treatment using substances that travel through the bloodstream, reaching and affecting cells all over the body.

A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and in women who are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate.

A type of treatment that uses drugs or other substances, such as monoclonal antibodies, to identify and attack specific cancer cells. Targeted therapy may have fewer side effects than other types of cancer treatments.

Treatment.

A group or layer of cells that work together to perform a specific function.

A monoclonal antibody that binds to HER2 (human epidermal growth factor receptor 2), and can kill HER2-positive cancer cells. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Trastuzumab is used to treat breast cancer that is HER2-positive and has spread after treatment with other drugs. It is also used with other anticancer drugs to treat HER2-positive breast cancer after surgery. Trastuzumab is also being studied in the treatment of other types of cancer. Also called Herceptin.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

Cancer that forms in tissues of the uterus (the small, hollow, pear-shaped organ in a woman's pelvis in which a fetus develops). Two types of uterine cancer are endometrial cancer (cancer that begins in cells lining the uterus) and uterine sarcoma (a rare cancer that begins in muscle or other tissues in the uterus).

The small, hollow, pear-shaped organ in a woman's pelvis. This is the organ in which a fetus develops. Also called womb.