1. What is a screening mammogram?

A screening mammogram is an x-ray of the breast used to detect breast changes in women who have no signs or symptoms of breast cancer. It usually involves two x-rays of each breast. Mammograms make it possible to detect tumors that cannot be felt. Mammograms can also find microcalcifications (tiny deposits of calcium in the breast) that sometimes indicate the presence of breast cancer.

2. How are screening and diagnostic mammograms different?

A diagnostic mammogram is an x-ray of the breast that is used to check for breast cancer after a lump or other sign or symptom of breast cancer has been found. Signs of breast cancer may include pain, skin thickening, nipple discharge, or a change in breast size or shape. A diagnostic mammogram also may be used to evaluate changes found during a screening mammogram, or to view breast tissue when it is difficult to obtain a screening mammogram because of special circumstances, such as the presence of breast implants (see Question 13). A diagnostic mammogram takes longer than a screening mammogram because it involves more x-rays in order to obtain views of the breast from several angles. The technician may magnify a suspicious area to produce a detailed picture that can help the doctor make an accurate diagnosis.

3. When does the National Cancer Institute (NCI) recommend that women have screening mammograms?



• Women age 40 and older should have mammograms every 1 to 2 years.
  
  
• Women who are at higher than average risk of breast cancer should talk with their health care providers about whether to have mammograms before age 40 and how often to have them.
  
  
4. What are the factors that place a woman at increased risk of breast cancer?

The risk of breast cancer increases gradually as a woman gets older. However, the risk of developing breast cancer is not the same for all women. Research has shown that the following factors increase a woman’s chance of developing this disease:

• Personal history of breast cancer—Women who have had breast cancer are more likely to develop a second breast cancer.

• Family history—A woman’s chance of developing breast cancer increases if her mother, sister, and/or daughter have a history of breast cancer (especially if they were diagnosed before age 50).

• Certain breast changes on biopsy—A diagnosis of atypical hyperplasia (a noncancerous condition in which cells have abnormal features and are increased in number) or lobular carcinoma in situ (LCIS) (abnormal cells found in the lobules of the breast) increases a woman’s risk of breast cancer. Women who have had two or more breast biopsies for other benign conditions also have an increased chance of developing breast cancer. This increased risk is due to the condition that led to the biopsy, and not to the biopsy itself.

• Genetic alterations (changes)—Specific alterations in certain genes (BRCA1, BRCA2, and others) increase the risk of breast cancer. These alterations are rare; they are estimated to account for no more than 10 percent of all breast cancers.

• Reproductive and menstrual history —Women who began having periods before age 12 or went through menopause after age 55 are at an increased risk of developing breast cancer. Women who have their first child after age 30 or who never have a child are at an increased risk of developing breast cancer.

• Long-term use of menopausal hormone therapy—Women who use combination estrogen-progestin menopausal hormone therapy for more than 5 years have an increased chance of developing breast cancer.

• Breast density —Breasts appear dense on a mammogram if they contain many glands and ligaments (called dense tissue), and do not have much fatty tissue. Because breast cancers tend to develop in the dense tissue of the breast (not in the fatty tissue), those older women whose mammograms show more dense tissue are at an increased risk of breast cancer. Abnormalities in dense breasts can be more difficult to detect on a mammogram.

• Radiation therapy ("x-ray therapy")—Women who had radiation therapy to the chest (including the breasts) before age 30 are at an increased risk of developing breast cancer throughout their lives. This includes women treated for Hodgkin lymphoma. Studies show that the younger a woman was when she received her treatment, the higher her risk of developing breast cancer later in life.

• DES (diethylstilbestrol) —The drug DES was given to some pregnant women in the United States between 1940 and 1971. (It is no longer given to pregnant women.) Women who took DES during pregnancy may have a slightly increased risk of breast cancer. The possible effects on their daughters are under study.

• Body weight—Studies have found that the chance of getting breast cancer after menopause is higher in women who are overweight or obese.

• Physical activity level —Women who are physically inactive throughout life may have an increased risk of breast cancer. Being active may help reduce risk by preventing weight gain and obesity.

• Alcohol —Studies suggest that the more alcohol a woman drinks, the greater her risk of breast cancer.

5. What are the chances that a woman in the United States might get breast cancer?

Age is the most important risk factor for breast cancer. The older a woman is, the greater her chance of developing breast cancer. Current rates suggest that 13.2 percent of women (or one in eight) born today will be diagnosed with breast cancer at some time in their lives. This statistic is based on population averages. However, the estimated chance of being diagnosed with breast cancer for specific age groups and for specific time periods may be a more informative way to consider breast cancer risk. Estimates of developing breast cancer in 10-year age intervals—as shown below—take into account that not all women live to older ages, when breast cancer risk becomes the greatest.

A woman’s chance of being diagnosed with breast cancer is:

from ages 30 to 39. . .	0.44 percent (often expressed as "1 in 229")
from ages 40 to 49. . .	1.46 percent (often expressed as "1 in 68")
from ages 50 to 59. . .	2.73 percent (often expressed as "1 in 37 ")
from ages 60 to 69. . .	3.82 percent (often expressed as "1 in 26 ")

Most breast cancers occur in women over the age of 50. The number of cases is especially high for women over age 60. Breast cancer is relatively uncommon in women under age 40. The NCI fact sheet Probability of Breast Cancer in American Women provides more information about lifetime risk. This fact sheet is available at http://www.cancer.gov/cancertopics/factsheet/Detection/probability-breast-cancer on the Internet.

6. What is the best method of detecting breast cancer as early as possible?

Getting a high-quality mammogram and having a clinical breast exam (an exam done by a health care provider) on a regular basis are the most effective ways to detect breast cancer early. Like any test, mammograms have both benefits and limitations. For example, some cancers cannot be detected by a mammogram, but may be found by breast examination.

Checking one’s own breasts for lumps or other unusual changes is called breast self-exam (BSE). Studies so far have not shown that BSE alone reduces the number of deaths from breast cancer. BSE should not take the place of routine clinical breast exams and mammograms.

7. What are the benefits of screening mammograms?

Several large studies conducted around the world show that breast cancer screening with mammograms reduces the number of deaths from breast cancer for women ages 40 to 69, especially those over age 50. Studies conducted to date have not shown a benefit from regular screening mammograms, or from a baseline screening mammogram (a mammogram used for comparison), in women under age 40.

8. What are some of the limitations of screening mammograms?
• Finding cancer does not always mean saving lives—Even though mammography can detect tumors that cannot be felt, finding a small tumor does not always mean that a woman’s life will be saved. Mammography may not help a woman with a fast-growing or aggressive cancer that has already spread to other parts of her body before being detected.

• False negatives —False negatives occur when mammograms appear normal even though breast cancer is present. Overall, mammograms miss up to 20 percent of the breast cancers that are present at the time of screening. False negatives occur more often in younger women than in older women because the dense breasts of younger women make breast cancers more difficult to detect in mammograms. As women age, their breasts usually become more fatty (and therefore less dense), and breast cancers become easier to detect with screening mammograms.

• False positives —False positives occur when mammograms are read by a radiologist as abnormal, but no cancer is actually present. All abnormal mammograms should be followed up with additional testing (a diagnostic mammogram, ultrasound, and/or biopsy) to determine if cancer is present. False positives are more common in younger women, women who have had previous breast biopsies, women with a family history of breast cancer, and women who are taking estrogen (for example, hormone replacement therapy).

9. What is the Breast Imaging Reporting and Database System (BI-RADS ®)?

The American College of Radiology (ACR) has established a uniform way for radiologists to report mammogram findings. The system, called BI-RADS, includes seven standardized categories, or levels. Each BI-RADS category has a follow-up plan associated with it to help radiologists and other physicians appropriately manage a patient’s care.

Breast Imaging Reporting and Database System (BI-RADS)
Category	Assessment	Follow-up
0	Need additional imaging evaluation	Additional imaging needed before a category can be assigned
1	Negative	Continue annual screening mammography (for women over age 40)
2	Benign (noncancerous) finding	Continue annual screening mammography (for women over age 40)
3	Probably benign	Receive a 6-month follow-up mammogram
4	Suspicious abnormality	May require biopsy
5	Highly suggestive of malignancy (cancer)	Requires biopsy
6	Known biopsy—proven malignancy (cancer)	Biopsy confirms presence of cancer before treatment begins

Further information on BI-RADS is available on the ACR Web site at http://www.acr.org/ on the Internet or by calling the ACR at 1–800–227–5463 (1–800–ACR–LINE).

10. What happens if mammography leads to the detection of ductal carcinoma in situ (DCIS)?

Over the past 30 years, improvements in mammography have made it possible to detect a higher number of tissue abnormalities called DCIS. DCIS is abnormal cells that are confined to the milk ducts of the breast. The cells have not invaded the surrounding breast tissue. DCIS usually does not cause a lump, so it cannot be detected during a clinical breast exam or BSE. However, mammography is able to detect 80 percent of DCIS cases. Some of these cases later become invasive cancers.

It is not possible to predict which cases of DCIS will progress to invasive cancer. Therefore, DCIS usually is removed surgically. Until recently, DCIS was often treated with a mastectomy, but breast-conserving therapy (breast-sparing surgery plus radiation therapy) is now standard practice for many women with DCIS. Tamoxifen may also be used. Women who have been diagnosed with DCIS should talk with their doctor to make an informed decision about treatment.

11. How much does a mammogram cost?

Screening mammograms generally cost between $50 and $150. Most states now have laws requiring health insurance companies to reimburse all or part of the cost of screening mammograms. Insurance companies and health care providers can supply details.

All women age 40 and older with Medicare can get a screening mammogram each year. Medicare will also pay for one baseline mammogram for a woman between the ages of 35 and 39. There is no deductible requirement for this benefit, but Medicare beneficiaries have to pay 20 percent of the Medicare-approved amount. Information about Medicare coverage is available at http://www.medicare.gov on the Internet, or through the Medicare Hotline at 1–800–633–4227 (1–800–MEDICARE). For the hearing impaired, the telephone number is 1–877–486–2048.

Some state and local health programs and employers provide mammograms free or at low cost. For example, the Centers for Disease Control and Prevention (CDC) coordinates the National Breast and Cervical Cancer Early Detection Program. This program provides screening services, including clinical breast exams and mammograms, to low-income women throughout the United States and in several U.S. territories. Contact information for local programs is available on the CDC’s Web site at http://apps.nccd.cdc.gov/cancercontacts/nbccedp/contacts.asp on the Internet, or by calling the CDC at 1–800–CDC–INFO (1–800–232–4636). Information on low-cost or free mammography screening programs is also available through the NCI’s Cancer Information Service (CIS) at 1–800–4–CANCER (1–800–422–6237).

12. Where can women get high-quality mammograms?

Women can get high quality mammograms in breast clinics, hospital radiology departments, mobile vans, private radiology offices, and doctors’ offices.

The Mammography Quality Standards Act (MQSA) is a Federal law designed to ensure that mammograms are safe and reliable. Through the MQSA, all mammography facilities in the United States must meet stringent quality standards, be accredited by the Food and Drug Administration (FDA), and be inspected annually. The FDA ensures that mammography facilities across the country meet MQSA standards. These standards apply to the following people at the mammography facility:

• The technologist who takes the mammogram.
• The radiologist who interprets the mammogram.
• The medical physicist who tests the mammography equipment.

Women can ask their doctors or staff at the mammography facility about FDA certification before making an appointment. All mammography facilities are required to display their FDA certificate. Women should look for the MQSA certificate at the mammography facility and check its expiration date. MQSA regulations also require mammography facilities to give patients an easy-to-read report on the results of their mammogram.

Information about local FDA-certified mammography facilities is available through the CIS at 1–800–4–CANCER (1–800–422–6237). Also, a list of these facilities is on the FDA’s Web site at http://www.fda.gov/cdrh/mammography/certified.html on the Internet.

13. What should women with breast implants do about screening mammograms?

Women with breast implants should continue to have mammograms. (A woman who had an implant following breast cancer surgery should ask her doctor whether a mammogram of the reconstructed breast is necessary.) It is important to inform the mammography facility about breast implants when scheduling a mammogram. The technician and radiologist must be experienced in x-raying patients with breast implants. Implants can hide some breast tissue, making it more difficult for the radiologist to detect an abnormality on the mammogram. If the technologist performing the procedure is aware a woman has breast implants, steps can be taken to make sure that as much breast tissue as possible can be seen on the mammogram.

14. What is digital mammography? How is it different from conventional (film) mammography?

Both digital and conventional mammography use x-ray radiation to produce an image of the breast; however, conventional mammography stores the image directly on film, whereas digital mammography takes an electronic image of the breast and stores it directly in a computer. This allows the recorded data to be enhanced, magnified, or manipulated for further evaluation. The difference between conventional mammography and digital mammography is like the difference between a traditional film camera and a new digital camera. Aside from the difference in how the image is recorded and stored, there is no other difference between the two.

In January 2000, the FDA approved the first digital mammography system. In September 2005, preliminary results from a large clinical trial (research study) of digital vs. film mammography were published. These findings show no difference between digital and film mammograms in detecting breast cancer for the general population of women in the trial. However, those women with dense breasts who are pre- or perimenopausal (women who had a last menstrual period within 12 months of their mammograms) or who are younger than age 50 may benefit from having a digital rather than a film mammogram.

Digital mammography allows a radiologist to electronically adjust, store, and retrieve digital images. These features may offer the following advantages over conventional mammography:

• Long-distance consultations with other mammography specialists may be easier.
• Subtle differences between normal and abnormal tissues may be easily noted.
• The number of follow-up procedures needed may be fewer.
• Fewer repeat images may be needed, reducing exposure to radiation.

Digital mammography can be done only in facilities that are certified to practice conventional mammography and have received FDA approval to offer digital mammography. The procedure for having a mammogram with a digital system is the same as with conventional mammography.

15. What other technologies are being developed for breast cancer screening?

The NCI is supporting the development of several new technologies to detect breast tumors. This research ranges from methods being developed in research labs to those that have reached clinical trials. Efforts to improve conventional mammography include digital mammography (see Question 14), magnetic resonance imaging (MRI), and positron emission tomography (PET scanning).

In addition to imaging technologies, NCI-supported scientists are exploring methods to detect markers ( genetic traits) of breast cancer in blood, urine, or nipple aspirates (fluid from the breast) that may serve as early warning signals for breast cancer. The NCI fact sheet Improving Methods for Breast Cancer Detection and Diagnosis provides more information about technologies that are under development for breast cancer screening and diagnosis. This fact sheet is available at http://www.cancer.gov/cancertopics/factsheet/Detection/breast-cancer on the Internet.

16. What studies is NCI supporting to find better ways to prevent and treat breast cancer?

NCI is supporting many studies to improve the prevention and treatment of breast cancer.

• Basic research —Researchers are working to identify the causes of breast cancer, including the role of changes in the BRCA1 and BRCA2 genes. They also are looking at how these genes interact with other genes and with hormonal, dietary, and environmental factors.

• Prevention —Researchers are looking for ways to prevent breast cancer in women who are at increased risk. For some of these women, the drugs tamoxifen and raloxifene have been shown to decrease the risk of developing breast cancer. Other medications are currently under study. Also, studies are evaluating how changes in diet, physical activity, nutrition, and environmental factors could lead to a reduced risk of developing breast cancer.

• Early detection and diagnosis —Several studies are seeking better ways to detect and diagnose breast cancer so women can receive treatment sooner.

• Treatment —Several studies are aimed at finding breast cancer treatments that are more effective and less toxic than current methods.

Related NCI materials and Web pages:

• National Cancer Institute Fact Sheet 5.6, Probability of Breast Cancer in American Women ¹
  (http://www.cancer.gov/cancertopics/factsheet/Detection/probability-breast-cancer)
• National Cancer Institute Fact Sheet 5.14, Improving Methods for Breast Cancer Detection and Diagnosis ²
  (http://www.cancer.gov/cancertopics/factsheet/Detection/breast-cancer)
• Breast Cancer Home Page ³
  (http://www.cancer.gov/cancertopics/types/breast)
• What You Need To Know About™ Breast Cancer ⁴
  (http://www.cancer.gov/cancertopics/wyntk/breast)

NCI’s Cancer Information Service
Telephone (toll-free): 1–800–4–CANCER (1–800–422–6237)
TTY (toll-free): 1–800–332–8615
LiveHelp^® online chat: https://cissecure.nci.nih.gov/livehelp/welcome.asp

Glossary Terms

Not normal. An abnormal lesion or growth may be cancerous, premalignant (likely to become cancer), or benign.

A quickly growing cancer.

A benign (noncancerous) condition in which cells look abnormal under a microscope and are increased in number.

Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body.

Breast Imaging Reporting and Data System. A method used by radiologists to interpret and report in a standardized manner the results of mammography, ultrasound, and MRI used in breast cancer screening and diagnosis. Also called Breast Imaging Reporting and Data System.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

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 gene on chromosome 17 that normally helps to suppress cell growth. A person who inherits a mutated (changed) BRCA1 gene has a higher risk of getting breast, ovarian, or prostate cancer.

A gene on chromosome 13 that normally helps to suppress cell growth. A person who inherits a mutated (changed) BRCA2 gene has a higher risk of getting breast, ovarian, or prostate cancer.

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

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.

Describes the relative amount of different tissues present in the breast. A dense breast has less fat than glandular and connective tissue. Mammogram films of breasts with higher density are harder to read and interpret than those of less dense breasts.

A silicone gel-filled or saline-filled sac placed under the chest muscle to restore breast shape.

An operation to remove the breast cancer but not the breast itself. Types of breast-sparing 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-conserving surgery.

A mineral found in teeth, bones, and other body tissues.

CIS. 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.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

Cancer that forms in tissues of the cervix (the organ connecting the uterus and vagina). It is usually a slow-growing cancer that may not have symptoms but can be found with regular Pap tests (a procedure in which cells are scraped from the cervix and looked at under a microscope).

An exam of the breast performed by a health care provider to check for lumps or other changes.

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 a clinical study.

Ductal carcinoma in situ. A noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, DCIS may become invasive cancer and spread to other tissues, although it is not known at this time how to predict which lesions will become invasive. Also called ductal carcinoma in situ and intraductal carcinoma.

Diethylstilbestrol. A synthetic form of the hormone estrogen that was prescribed to pregnant women between about 1940 and 1971 because it was thought to prevent miscarriages. DES may increase the risk of uterine, ovarian, or breast cancer in women who took it. It also has been linked to an increased risk of clear cell carcinoma of the vagina or cervix in daughters exposed to DES before birth. Also called diethylstilbestrol.

The process of identifying a disease, such as cancer, from its signs and symptoms.

X-ray of the breasts used to check for breast cancer after a lump or other sign or symptom of breast cancer has been found.

The things a person eats and drinks.

DES. A synthetic form of the hormone estrogen that was prescribed to pregnant women between about 1940 and 1971 because it was thought to prevent miscarriages. DES may increase the risk of uterine, ovarian, or breast cancer in women who took it. DES also has been linked to an increased risk of clear cell carcinoma of the vagina or cervix in daughters exposed to DES before birth. Also called DES.

A technique that uses a computer, rather than x-ray film, to record x-ray images of the breast.

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.

In medicine, a tube or vessel of the body through which fluids pass.

The most common type of breast cancer. It begins in the cells that line the milk ducts in the breast.

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 record of a person's current and past illnesses, and those of his or her parents, brothers, sisters, children, and other family members. A family history shows the pattern of certain diseases in a family, and helps to determine risk factors for those and other diseases.

Liquid.

Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.

An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk. Endocrine glands release the substances directly into the bloodstream. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.

HRT. Hormones (estrogen, progesterone, or both) given to women after menopause to replace the hormones no longer produced by the ovaries. Also called HRT and menopausal hormone therapy.

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.

A substance or object that is put in the body as a prosthesis, or for treatment or diagnosis.

Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.

Lobular carcinoma in situ. A condition in which abnormal cells are found in the lobules of the breast. LCIS seldom becomes invasive cancer; however, having it in one breast increases the risk of developing breast cancer in either breast. Also called lobular carcinoma in situ.

Cancer that begins in the lobules (the glands that make milk) of the breast. Lobular carcinoma in situ (LCIS) is a condition in which abnormal cells are found only in the lobules. When cancer has spread from the lobules to surrounding tissues, it is invasive lobular carcinoma. LCIS does not become invasive lobular carcinoma very often, but having LCIS in one breast increases the risk of developing invasive cancer in either breast.

A small lobe or a subdivision of a lobe.

Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. Magnetic resonance imaging makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. Magnetic resonance imaging is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called MRI, nuclear magnetic resonance imaging, and NMRI.

A cancerous tumor that can invade and destroy nearby tissue and spread to other parts of the body.

An x-ray of the breast.

The use of x-rays to create a picture of the breast.

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

Hormones (estrogen, progesterone, or both) given to women after menopause to replace the hormones no longer produced by the ovaries. Also called hormone replacement therapy and HRT.

The time of life when a woman's menstrual periods stop. A woman is in menopause when she hasn't had a period for 12 months in a row. Also called change of life.

The monthly cycle of hormonal changes from the beginning of one menstrual period to the beginning of the next.

The periodic discharge of blood and tissue from the uterus. From puberty until menopause, menstruation occurs about every 28 days, but does not occur during pregnancy.

A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, nuclear magnetic resonance imaging, and NMRI.

The National Cancer Institute, 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. The National Cancer Institute 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 National Cancer Institute Web site at http://www.cancer.gov. Also called NCI.

Fluid coming from the nipple.

The taking in and use of food and other nourishing material by the body. Nutrition is a 3-part process. First, food or drink is consumed. Second, the body breaks down the food or drink into nutrients. Third, the nutrients travel through the bloodstream to different parts of the body where they are used as "fuel" and for many other purposes. To give the body proper nutrition, a person has to eat and drink enough of the foods that contain key nutrients.

Having an abnormally high, unhealthy amount of body fat.

Being too heavy for one’s height. Excess body weight can come from fat, muscle, bone, and/or water retention. Being overweight does not always mean being obese.

The time of a woman's life when menstrual periods become irregular. Refers to the time just before menopause.

Medical doctor.

PET scan. A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called PET scan.

Any natural or laboratory-made substance that has some or all of the biologic effects of progesterone, a female hormone.

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 radiotherapy and irradiation.

A doctor who specializes in creating and interpreting pictures of areas inside the body. The pictures are produced with x-rays, sound waves, or other types of energy.

A drug used to reduce the risk of invasive breast cancer in postmenopausal women who are at a high risk of developing the disease or who have osteoporosis. It is also used to prevent and treat osteoporosis in postmenopausal women and is being studied in the prevention and treatment of other conditions. Raloxifene blocks the effects of the hormone estrogen in the breast and increases the amount of calcium in bone. It is a type of selective estrogen receptor modulator (SERM). Also called raloxifene hydrochloride and Evista.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

X-rays of the breasts taken to check for breast cancer in the absence of signs or symptoms.

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

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

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 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 and Nolvadex.

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

Having to do with poison or something harmful to the body. Toxic substances usually cause unwanted side effects.

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 cancerous), or malignant (cancerous). Also called neoplasm.

A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echo patterns are shown on the screen of an ultrasound machine, forming a picture of body tissues called a sonogram. Also called ultrasonography.

Fluid containing water and waste products. Urine is made by the kidneys, stored in the bladder, and leaves the body through the urethra.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.

A type of radiation therapy that uses high-energy radiation from x-rays to kill cancer cells and shrink tumors.