Mammography

Definition

Mammography is the study of the breast using x ray. The actual test is called a mammogram. There are two types of mammograms. A screening mammogram is ordered for women who have no problems with their breasts. It consists of two x-ray views of each breast. A diagnostic mammogram is for evaluation of new abnormalities or of patients with a past abnormality requiring follow-up (i.e., a woman with breast cancer treated with lumpectomy ). Additional x rays from other angles or special views of certain areas are taken.

Purpose

The purpose of screening mammography is breast cancer detection. A screening test, by definition, is used for patients without any signs or symptoms in order to detect disease as early as possible. Many studies have shown that having regular mammograms increases a woman's chances of finding breast cancer in an early stage, when it is more likely to be curable. It has been estimated that a mammogram may find a cancer as much as two years before it can be felt. The American Cancer Society, American College of Radiology, American College of Surgeons and American Medical Association recommend annual mammograms for every woman beginning at age 40.

Screening mammograms usually are not recommended for women under age 40 who have no special risk factors and a normal physical breast examination. Below age 40, breasts tend to be "radiographically dense," which means it is difficult to see many details. In 2003, a new technique that introduces radiographic contrast into digital mammograms was proving useful at improving visibility of breast cancer in younger women. Screening mammograms can detect cancers in their earliest stages and greatly reduce mortality, particularly among women age 40 to 69. In fact, a study in 2003 found that women age 40 and older who had annual screening mammograms had better breast cancer prognoses because their cancers were diagnosed at earlier stages than women who had mammograms less often.

Some women are at increased risk for developing breast cancer, such as those with two or more relatives who have the disease. The 2003 American Cancer Society guidelines stated that women at increased risk might benefit from earlier screening mammograms and more frequent intervals for screening. However, the society suggested that evidence was not strong enough at that time to support making specific recommendations concerning screening examinations.

Diagnostic mammography is used to evaluate an existing problem, such as a lump, discharge from the nipple, or unusual tenderness in one area. The cause of the problem may be definitively diagnosed from this study, but further investigation using other methods often is necessary. This exam also is used to evaluate findings from screening mammography.

Description

A mammogram may be offered in a variety of settings. Hospitals, outpatient clinics, physicians' offices, or other facilities may have mammography equipment. In the United States, since October 1, 1994, only places certified by the U.S. Food and Drug Administration (FDA) are legally permitted to perform, interpret, or develop mammograms under the Mammography Quality Standards Act (MQSA).

In addition to the usual paperwork, a woman will be asked to fill out a form seeking information relevant to her risk of breast cancer and special mammography needs. The woman is asked about personal and family history of cancer, details about menstruation, child bearing, birth control, breast implants, other breast surgery, age, and hormone replacement therapy. Information about Breast Self Examination (BSE) and other breast health issues usually are available at no charge.

At some centers, a technologist may perform a physical examination of the breasts before the mammogram. Whether or not this is done, it is essential for the patient to tell the technologist about any lumps, nipple discharge, breast pain, or other concerns.

Clothing from the waist up is removed and a hospital gown or similar covering is put on. The woman stands facing the mammography machine. The technologist exposes one breast and places it on a plastic or metal film holder about the size of a placemat. The breast is compressed as flat as possible between the film holder and a rectangle of plastic (called a paddle), which presses down onto the breast from above. The compression should only last a few seconds, just enough to take the x ray. Good compression can be uncomfortable, but it is necessary to ensure the clearest view of all breast tissues.

Next, the woman is positioned with her side toward the mammography unit. The film holder is tilted so the outside of the breast rests against it, and a corner touches the armpit. The paddle again holds the breast firmly as the x ray is taken. This procedure is repeated for the other breast. A total of four x rays, two of each breast, are taken for a screening mammogram. Additional x rays, using special paddles, different breast positions, or other techniques are usually taken for a diagnostic mammogram.

The mammogram may be seen and interpreted by a radiologist right away, or it may not be reviewed until later. If there are any questionable areas or an abnormality, extra x rays may be recommended. These may be taken during the same appointment. More commonly, especially for screening mammograms, the woman is called back on another day for these additional films.

A screening mammogram usually takes approximately 15 to 30 minutes. A woman having a diagnostic mammogram can expect to spend up to an hour at the mammography facility.

The cost of mammography varies widely. Many mammography facilities accept "self referral." This means women can schedule themselves without a physician's referral. However, some insurance policies require a doctor's prescription to ensure payment. Medicare will pay for annual screening mammograms for all women with Medicare who are age 40 or older and a baseline mammogram for those age 35 to 39.

A digital mammogram is performed in the same way as a traditional exam, but the image is viewed on a computer monitor, stored as a digital file, and can be printed on film. Medicare now pays a small additional fee for digital mammography.

Preparation

The compression or squeezing of the breast for a mammogram is a concern for some women, but necessary to render a quality image. Even with concerns about pain, a 2003 study said that three-fourths of women reported the pain associated with a mammogram as four on a 10-point scale. Mammograms should be scheduled when a woman's breasts are least likely to be tender. One week after the menstrual period is usually best. The MQSA regulates equipment compression for consistency and performance.

Women should not put deodorant, powder, or lotion on their upper body on the day the mammogram is performed. Particles from these products can get on the breast or film holder and may look like abnormalities on the mammogram film.

Aftercare

No special aftercare is required.

Risks

The risk of radiation exposure from a mammogram is considered virtually nonexistent. Experts are unanimous that any negligible risk is far outweighed by the potential benefits of mammography.

Some breast cancers do not show up on mammograms, or "hide" in dense breast tissue. A normal (or negative) study is not a guarantee that a woman is cancer-free. Mammograms find about 85% to 90% of breast cancers.

"False positive" readings also are possible, and 5% to 10% of mammogram results indicate the need for additional testing, most of which confirm that no cancer is present.

Normal results

A mammography report describes details about the x ray appearance of the breasts. It also rates the mammogram according to standardized categories, as part of the Breast Imaging Reporting and Data System (BIRADS) created by the American College of Radiology (ACR). A normal mammogram may be rated as BIRADS 1 or negative, which means no abnormalities were seen. A normal mammogram may also be rated as BIRADS 2 or benign findings. This means that one or more abnormalities were found but are clearly benign (not cancerous), or variations of normal. Some kinds of calcification, lymph nodes, or implants in the breast might generate a BIRADS 2 rating. A BIRADS 0 rating indicates that the mammogram is incomplete and requires further assessment.

Abnormal results

Many mammograms are considered borderline or indeterminate in their findings. BIRADS 3 means an abnormality is present and probably (but not definitely) benign. A follow-up mammogram within a short interval of six months is suggested. This helps to ensure that the abnormality is not changing, or is "stable." This stability in the abnormality indicates that a cancer is probably not present. If the abnormality is cancerous, it will likely grow and change in the time between mammograms. Some women are uncomfortable or anxious about waiting and may want to consult with their doctor about having a biopsy. BIRADS 4 means suspicious for cancer. A biopsy is usually recommended in this case. BIRADS 5 means an abnormality is highly suggestive of cancer. The suspicious area should be biopsied.

Often, screening mammograms are followed up with additional imaging. The reasons are numerous; they may mot mean the radiologist suspects a cancerous lesion, only that he or she cannot make a clear diagnosis from the screening mammogram views. The most common imaging methods are additional views on the mammogram, sometimes called magnification views, and ultrasound. In recent years, some patients have received magnetic resonance imaging (MRI) of the breast. A new technique called dual-energy contrast enhanced digital subtraction mammography is reported to find cancers that may be missed by conventional mammography. It may be ordered in the future as a follow-up study.

KEY TERMS

Breast biopsy— A procedure in which suspicious tissue is removed and examined by a pathologist for cancer or other disease. The breast tissue may be obtained by open surgery or through a needle.

Radiographically dense— Difficult to see details of breast tissue on x ray.

Resources

BOOKS

Henderson, Craig. Mammography & Beyond. Developing Technologies for the Early Detection of Breast Cancer: A Non-technical Summary. Washington, DC: National Academy Press, 2001.

Love, Susan M., with Karen Lindsey. Dr. Susan Love's Breast Book. 3rd ed. Boulder, CO: Perseus Book Group, 2000.

PERIODICALS

"Contrast Mammography Reveals Hard-to-find Cancers." Cancer Weekly October 14, 2003: 34.

"Mammography in Women Over Forty Catches Disease Earlier." Women's Health Weekly August 14, 2003: 14.

"New Digital Technique Improves Mammography Results." Women's Health Weekly September 18, 2003: 28.

Smith, Robert A., et al. "American Cancer Society Guidelines for Breast Cancer Screening: Update 2003." Cancer May-June 2003: 141-170.

"Stress—Not Pain—Is Major Barrier to Mammography." Contemporary OB/GYN July 2003: 17.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Rd., Atlanta, GA 30329. (800) ACS-2345. 〈http://www.cancer.org〉.

National Cancer Institute. Office of Cancer Communications, Bldg. 31, Room 10A31, Bethesda, MD 20892. NCI/Cancer Information Service: (800) 4-CANCER. 〈http://cancernet.nci.nih.gov〉.

U.S. Food and Drug Administration. 5600 Fishers Lane, Rockville, MD 20857. (800) 532-4440. 〈http://www.fda.gov〉.

Mammography

Definition

Mammography is the study of the breast using x rays. The actual test is called a mammogram. It is an x ray of the breast which shows the fatty, fibrous and glandular tissues. There are two types of mammograms. A screening mammogram is ordered for women who have no problems with their breasts. It consists of two x-ray views of each breast: a craniocaudal (from above) and a mediolateral oblique (from the sides). A diagnostic mammogram is for evaluation of abnormalities in either men or women. Additional x rays from other angles, or special coned views of certain areas, are taken.

Purpose

The purpose of screening mammography is breast cancer detection. A screening test, by definition, is used for patients without any signs or symptoms, in order to detect disease as early as possible. Many studies have shown that having regular mammograms increases a woman's chances of finding breast cancer in an early stage, when it is more likely to be curable. It has been estimated that a mammogram may find a cancer as much as two or three years before it can be felt. The American Cancer Society (ACS) guidelines recommend an annual screening mammogram for every woman of average risk beginning at age 40. Radiologists look specifically for the presence of microcalcifications and other abnormalities that can be associated with malignancy. New digital mammography and computer aided reporting can automatically enhance and magnify the mammograms for easier finding of these tiny calcifications.

The highest risk factor for developing cancer is age. Some women are at an increased risk for developing breast cancer, such as those with a positive family history of the disease. Beginning screening mammography at a younger age may be recommended for these women.

Diagnostic mammography is used to evaluate an existing problem, such as a lump, discharge from the nipple, or unusual tenderness in one area. It is also done to evaluate further abnormalities that have been seen on screening mammograms. The radiologist normally views the films immediately and may ask for additional views such as a magnification view of one specific area. Additional studies such as an ultrasound of the breast may be performed as well to determine if the lesion is cystic or solid. Breast-specific positron emission tomography (PET) scans as well as in MRI (magnetic resonance imaging ) may be ordered to further evaluate a tumor, but mammography is still the first choice in detecting small tumors on a screening basis.

Precautions

Screening mammograms are not usually recommended for women under age 40 who have no special risk factors and a normal physical breast examination. A mammogram may be useful if a lump or other problem is discovered in a woman aged 30-40. Below age 30, breasts tend to be "radiographically dense," which means the breasts contain a large amount of glandular tissue which is difficult to image in fine detail. Mammograms for this age group are controversial. An ultrasound of the breasts is usually done instead since it gives no radiation to the patient.

Description

A mammogram may be offered in a variety of settings. Hospitals, outpatient clinics, physician's offices, or other facilities may have mammography equipment. In the United States only places certified by the Food and Drug Administration (FDA) are legally permitted to perform, interpret, or develop mammograms. Mammograms are taken with dedicated machines using high frequency generators, low kvp, molybdenum targets and specialized x-ray beam filtration. Sensitive high contrast film and screen combinations along with prolonged developing enable the visualization of minute breast detail.

In addition to the usual paperwork, a woman will be asked to fill out a questionaire asking for information on her current medical history. Beyond her personal and family history of cancer, details about menstruation, previous breast surgeries, child bearing, birth control, and hormone replacement therapy are recorded. Information about breast self-examination (BSE) and other breast health issues are usually available at no charge.

At some centers, a technologist may perform a physical examination of the breasts before the mammogram. Whether or not this is done, it is essential for the technologist to record any lumps, nipple discharge, breast pain or other concerns of the patient. All visible scars, tattoos and nipple alterations must be carefully noted as well.

Clothing from the waist up is removed, along with necklaces and dangling earrings. A hospital gown or similar covering is put on. A small self-adhesive metal marker may be placed on each nipple by the x-ray technologist. This allows the nipple to be viewed as a reference point on the film for concise tumor location and easier centering for additional views.

Patients are positioned for mammograms differently, depending on the type of mammogram being performed:

• Craniocaudal position (CC): The woman stands or sits facing the mammogram machine. One breast is exposed and raised to a level position while the height of the cassette-holder is adjusted to the same level. The breast is placed mid-film with the nipple in profile and the head turned away from the side being x rayed. The shoulder is relaxed and pulled slightly backward while the breast is pulled as far forward as possible. The technologist holds the breast in place and slowly lowers the compression with a foot pedal. The breast is compressed between the film holder and a rectangle of plastic (called a paddle). The breast is compressed until the skin is taut and the breast tissue firm when touched on the lateral side. The exposure is taken immediately and the compression released. Good compression can be uncomfortable, but it is very necessary. Compression reduces the thickness of the breast, creates a uniform density and separates over-lying tissues. This allows for a detailed image with a lower exposure time and decreased radiation dose to the patient. The same view is repeated on the opposite breast.
• Mediolateral oblique position (MLO): The woman is positioned with her side towards the mammography unit. The film holder is angled parallel to the pectoral muscle, anywhere from 30 to 60 degrees depending on the size and height of the patient. The taller and thinner the patient the higher the angle. The height of the machine is level with the axilla (armpit). The arm is placed at the top of the cassette-holder with a corner touching the armpit. The breast is lifted forward and upward and compression is applied until the breast is held firmly in place by the paddle. The nipple should be in profile and the opposite breast held away if necessary by the patient. This procedure is repeated for the other breast. A total of four x rays, two of each breast, are taken for a screening mammogram. Additional x rays, using special paddles, different breast positions, or other techniques may be taken for a diagnostic mammogram.

The mammogram may be seen and interpreted by a radiologist right away, or it may not be reviewed until later. If there is any questionable area or abnormality, extra x rays may be recommended. These may be taken during the same appointment. More commonly, especially for screening mammograms, the woman is called back on another day for these additional films.

A screening mammogram usually takes approximately 15-30 minutes. A woman having a diagnostic mammogram can expect to spend up to an hour for the procedure.

The cost of mammography varies widely. Many mammography facilities accept "self referral." This means women can schedule themselves without a physician's referral. However, some insurance policies do require a doctor's prescription to ensure payment. Medicare will pay for annual screening mammograms for all women over age 39.

Preparation

The compression or squeezing of the breast necessary for a mammogram is a concern of many women. Mammograms should be scheduled when a woman's breasts are least likely to be tender. One to two weeks after the first day of the menstrual period is usually best. Some women with sensitive breasts also find that stopping or decreasing caffeine intake from coffee, tea, colas, and chocolate for a week or two before the examination decreases any discomfort. Women receiving hormone therapy may also have sensitive breasts. Over-the-counter pain relievers are recommended an hour before the mammogram appointment when pain is a significant problem.

Women should not put deodorant, powder, or lotion on their upper body on the day the mammogram is performed. Particles from these products can get on the breast or film holder and may show up as abnormalities on the mammogram. Most facilities will have special wipes available for those patients who need to wash before the mammogram.

Aftercare

No special aftercare is required.

Complications

The risk of radiation exposure from a mammogram is considered minimal and not significant. Experts are unanimous that any negligible risk is by far outweighed by the potential benefits of mammography. Patients who have breast implants must be x rayed with caution and compression is minimally applied so that the sac is not ruptured. Special techniques and positioning skills must be learned before a technologist can x ray a patient with breast implants.

Some breast cancers do not show up on mammograms, or "hide" in dense breast tissue. A normal (or negative) study is not a guarantee that a woman is cancer-free. The false-negative rate is estimated to be 15-20%, higher in younger women and women with dense breasts.

False positive readings are also possible. Breast biopsies may be recommended on the basis of a mammogram, and find no cancer. It is estimated that 75-80% of all breast biopsies resulted in benign (no cancer present) findings. This is considered an acceptable rate, because recommending fewer biopsies would result in too many missed cancers.

Results

A mammography report describes details about the x ray appearance of the breasts. It also rates the mammogram according to standardized categories, as part of the Breast Imaging Reporting and Data System (BIRADS) created by the American College of Radiology (ACR). A normal mammogram may be rated as BIRADS 1 or negative, which means no abnormalities were seen. A normal mammogram may also be rated as BIRADS 2 or benign findings. This means there are one or more abnormalities but they are clearly benign (not cancerous), or variations of normal. Some kinds of calcifications, enlarged lymph nodes or obvious cysts might generate a BIRADS 2 rating.

Many mammograms are considered borderline or indeterminate in their findings. BIRADS 3 means either additional images are needed, or an abnormality is seen and is probably (but not definitely) benign. A follow-up mammogram within a short interval of six to twelve months is suggested. This helps to ensure that the abnormality is not changing, or is "stable." Only the affected side will be x rayed at this time. Some women are uncomfortable or anxious about waiting, and may want to consult with their doctor about having a biopsy. BIRADS 4 means suspicious for cancer. A biopsy is usually recommended in this case. BIRADS 5 means an abnormality is highly suggestive of cancer. A biopsy or other appropriate action should be taken.

Health care team roles

The mammographic x-ray technologist works closely with the radiologist. Films of high quality must be taken so the radiologist can make an accurate diagnosis. The technologist also assists the radiologist when performing biopsies or fine needle aspirations. Analysis of the specimen will be carried out in the laboratory by the medical laboratory technician. It is important for the technologist to fill out the proper laboratory forms. Biopsies performed in the operating room will sometimes require a magnified x ray of the specimen itself. The technologist must work in conjunction with the surgeon and operating room nurses to make sure the specimen is x rayed immediately and than returned for further analysis.

All radiology technologists must be certified according to a recognized standard such as that of the American Society of Registered Radiology Technologists. The MQSA, or Mammography Quality Standards Act, enforced by the FDA, ensures that all mammographic x-ray technologists receive adequate training and continued education to perform special techniques such as mammography of patients with breast implants. It is also part of the technologist's or nurse's job to perform quality assurance and to keep statistics to ensure FDA compliance.

Patient education

The mammography technologist must be empathetic to the patient's modesty and anxiety. He or she must explain that compression is necessary to improve the quality of the image but does not harm the breasts. Patients will be very anxious when additional films are requested. Explaining that an extra view will give the radiologist more information will help to eases the patient's tension. One in eight women in North America will develop breast cancer. Educating the public on monthly breast self-examinations and yearly mammograms will help in achieving an early diagnosis and therefore a better cure.

KEY TERMS

Breast biopsy— A procedure where suspicious tissue is removed and examined by a pathologist for cancer or other disease. The breast tissue may be obtained by open surgery, or through a needle.

Craniocaudal— Head to tail, x-ray beam directly overhead the part being examined.

Radiographically dense— An abundance of glandular tissue, which results in diminished film detail.

Resources

PERIODICALS

Carmen, Ricard, R. T. R. Mammography: Techniques and Difficulties. O. T. R. Q., 1999.

Gagnon, Gilbert. Radioprotection in Mammography. O. T. R. Q., 1999.

Ouimet, Guylaine, R. T. R. Mammography: Quality Control. O. T. R. Q., 1999.

ORGANIZATIONS

American Cancer Society (ACS), 1599 Clifton Rd., Atlanta, GA 30329. (800) ACS-2345. 〈http://www.cancer.org〉.

Federal Drug Administration (FDA), 5600 Fishers Ln., Rockville, MD 20857. (800) 532-4440. 〈http://www.fda.gov〉.

National Cancer Institute (NCI) and Cancer Information Service (CIS), Office of Cancer Communications, Bldg. 31, Room 10A16, Bethesda, MD 20892. (800) 4-CANCER (800) 422-6237. Fax: (800) 624-2511 or (301) 402-5874. 〈http://cancernet.nci.nih.gov〉. cancermail@cips.nci.nih.gov.

Mammography

Definition
Purpose
Description
Preparation
Aftercare
Risks
Normal results

Definition

Mammography is the study of the breast using x rays. The actual test is called a mammogram. It is an x ray of the breast which shows the fatty, fibrous, and glandular tissues. There are two types of mammograms. A screening mammogram is ordered for women who have no problems with their breasts. It consists of two x-ray views of each breast: a craniocaudal (from above) and a mediolateral oblique (from the sides). A diagnostic mammogram is for evaluation of abnormalities in either men or women. Additional x rays from other angles, or special coned views of certain areas, are taken.

Purpose

The purpose of screening mammography is breast cancer detection. A screening test, by definition, is used for patients without any signs or symptoms, in order to detect disease as early as possible. Many studies have shown that having regular mammograms increases a woman’s chances of finding breast cancer in an early stage, when it is more likely to be curable. It has been estimated that a mammogram may find a cancer as much as two or three years before it can be felt. The American Cancer Society (ACS) guidelines recommend an annual screening mammogram for every woman of average risk beginning at age 40. Radiologists look specifically for the presence of microcalcifications and other abnormalities that can be associated with malignancy. New digital mammography and computer-aided reporting can automatically enhance and magnify the mammograms for easier identification of these tiny calcifications.

The highest risk factor for developing cancer is age. Some women are at an increased risk for developing breast cancer, such as those with a positive family history of the disease. Beginning screening mammography at a younger age may be recommended for these women.

Diagnostic mammography is used to evaluate an existing problem, such as a lump, discharge from the nipple, or unusual tenderness in one area. It is also done to evaluate further abnormalities that have been seen on screening mammograms. The radiologist normally views the films immediately and may ask for additional views such as a magnification view of one specific area. Additional studies such as an ultrasound of the breast may be performed as well to determine if the lesion is cystic or solid. Breast-specific positron emission

KEY TERMS

Breast biopsy— A procedure where suspicious tissue is removed and examined by a pathologist for cancer or other disease. The breast tissue may be obtained by open surgery, or through a needle.

Craniocaudal— Head to tail, x-ray beam directly overhead the part being examined.

Radiographically dense— An abundance of glandular tissue that results in diminished anatomic detail on the mammogram.

tomography (PET) scans as well as an MRI (magnetic resonance imaging ) may be ordered to further evaluate a tumor, but mammography is still the first choice in detecting small tumors on a screening basis.

Description

A mammogram may be offered in a variety of settings. Hospitals, outpatient clinics, physician’s offices, or other facilities may have mammography equipment. In the United States only places certified by the Food and Drug Administration (FDA) are legally permitted to perform, interpret, or develop mammograms. Mammograms are taken with dedicated machines using high frequency generators, low kvp, molybdenum targets and specialized x-ray beam filtration. Sensitive high contrast film and screen combinations along with prolonged developing enable the visualization of minute breast detail.

In addition to the usual paperwork, a woman will be asked to fill out a questionnaire asking for information on her current medical history. Beyond her personal and family history of cancer, details about menstruation, previous breast surgeries, child bearing, birth control, and hormone replacement therapy are recorded. Information about breast self-examination (BSE) and other breast health issues are usually available at no charge.

At some centers, a technologist may perform a physical examination of the breasts before the mammogram. Whether or not this is done, it is essential for the technologist to record any lumps, nipple discharge, breast pain or other concerns of the patient. All visible scars, tattoos and nipple alterations must be carefully noted as well.

Clothing from the waist up is removed, along with necklaces and dangling earrings. A hospital gown or similar covering is put on. A small self-adhesive metal marker may be placed on each nipple by the x-ray technologist. This allows the nipple to be viewed as a reference point on the film for concise tumor location and easier centering for additional views.

Patients are positioned for mammograms differently, depending on the type of mammogram being performed:

• Craniocaudal position (CC): The woman stands or sits facing the mammogram machine. One breast is exposed and raised to a level position while the height of the cassette holder is adjusted to the same level. The breast is placed mid-film with the nipple in profile and the head turned away from the side being x rayed. The shoulder is relaxed and pulled slightly backward while the breast is pulled as far forward as possible. The technologist holds the breast in place and slowly lowers the compression with a foot pedal. The breast is compressed between the film holder and a rectangle of plastic (called a paddle). The breast is compressed until the skin is taut and the breast tissue firm when touched on the lateral side. The exposure is taken immediately and the compression released. Good compression can be uncomfortable, but it is very necessary. Compression reduces the thickness of the breast, creates a uniform density and separates overlying tissues. This allows for a detailed image with a lower exposure time and decreased radiation dose to the patient. The same view is repeated on the opposite breast.
• Mediolateral oblique position (MLO): The woman is positioned with her side towards the mammography unit. The film holder is angled parallel to the pectoral muscle, anywhere from 30 to 60 degrees depending on the size and height of the patient. The taller and thinner the patient the higher the angle. The height of the machine is level with the axilla (armpit). The arm is placed at the top of the cassette holder with a corner touching the armpit. The breast is lifted forward and upward and compression is applied until the breast is held firmly in place by the paddle. The nipple should be in profile and the opposite breast held away if necessary by the patient. This procedure is repeated for the other breast. A total of four x rays, two of each breast, are taken for a screening mammogram. Additional x rays, using special paddles, different breast positions, or other techniques may be taken for a diagnostic mammogram.

The mammogram may be seen and interpreted by a radiologist right away, or it may not be reviewed until later. If there is any questionable area or abnormality, extra x rays may be recommended. These may be taken during the same appointment. More commonly, especially for screening mammograms, the woman is called back on another day for these additional films.

A screening mammogram usually takes approximately 15 to 30 minutes. A woman having a diagnostic mammogram can expect to spend up to an hour for the procedure.

The cost of mammography varies widely. Many mammography facilities accept “self referral.” This means women can schedule themselves without a physician’s referral. However, some insurance policies do require a doctor’s prescription to ensure payment. Medicare will pay for annual screening mammograms for all women over age 39.

Preparation

The compression or squeezing of the breast necessary for a mammogram is a concern of many women. Mammograms should be scheduled when a woman’s breasts are least likely to be tender. One to two weeks after the first day of the menstrual period is usually best, as the breasts may be tender during a menstrual period. Some women with sensitive breasts also find that stopping or decreasing caffeine intake from coffee, tea, colas, and chocolate for a week or two before the examination decreases any discomfort. Women receiving hormone therapy may also have sensitive breasts. Over-the-counter pain relievers are recommended an hour before the mammogram appointment when pain is a significant problem.

Women should not put deodorant, powder, or lotion on their upper body on the day the mammogram is performed. Particles from these products can get on the breast or film holder and may show up as abnormalities on the mammogram. Most facilities will have special wipes available for those patients who need to wash before the mammogram.

Aftercare

No special aftercare is required.

Risks

The risk of radiation exposure from a mammogram is considered minimal and not significant. Experts are unanimous that any negligible risk is by far outweighed by the potential benefits of mammography. Patients who have breast implants must be x rayed with caution and compression is minimally applied so that the sac is not ruptured. Special techniques and positioning skills must be learned before a technologist can x ray a patient with breast implants.

Some breast cancers do not show up on mammograms, or “hide” in dense breast tissue. A normal (or negative) study is not a guarantee that a woman is cancer-free. The false-negative rate is estimated to be 15–20%, higher in younger women and women with dense breasts.

False positive readings are also possible. Breast biopsies may be recommended on the basis of a mammogram, and find no cancer. It is estimated that 75–80% of all breast biopsies resulted in benign (no cancer present) findings. This is considered an acceptable rate, because recommending fewer biopsies would result in too many missed cancers.

Normal results

A mammography report describes details about the x-ray appearance of the breasts. It also rates the mammogram according to standardized categories, as part of the Breast Imaging Reporting and Data System (BIRADS) created by the American College of Radiology (ACR). A normal mammogram may be rated as BIRADS 1 or negative, which means no abnormalities were seen. A normal mammogram may also be rated as BIRADS 2 or benign findings. This means there are one or more abnormalities but they are clearly benign (not cancerous), or variations of normal. Some kinds of calcifications, enlarged lymph nodes or obvious cysts might generate a BIR-ADS 2 rating.

Many mammograms are considered borderline or indeterminate in their findings. BIRADS 3 means either additional images are needed, or an abnormality is seen and is probably (but not definitely) benign. A follow-up mammogram within a short interval of six to 12 months is suggested. This helps to ensure that the abnormality is not changing, or is “stable.” Only the affected side will be x rayed at this time. Some women are uncomfortable or anxious about waiting, and may want to consult with their doctor about having a biopsy. BIRADS 4 means suspicious for cancer. A biopsy is usually recommended in this case. BIRADS 5 means an abnormality is highly suggestive of cancer. A biopsy or other appropriate action should be taken.

Screening mammograms are not usually recommended for women under age 40 who have no special risk factors and a normal physical breast examination. A mammogram may be useful if a lump or other problem is discovered in a woman aged 30-40. Below age 30, breasts tend to be “radiographically dense,” which means the breasts contain a large amount of glandular tissue which is difficult to image in fine detail. Mammograms for this age group are controversial. An ultrasound of the breasts is usually done instead.

Patient education

The mammography technologist must be empathetic to the patient’s modesty and anxiety. He or she must explain that compression is necessary to improve the quality of the image but does not harm the breasts. Patients may be very anxious when additional films are requested. Explaining that an extra view gives the radiologist more information will help to ease the patient’s tension. One in eight women in North America will develop breast cancer. Educating the public on monthly breast self-examinations and yearly mammograms will help in achieving an early diagnosis and therefore a better cure.

Resources

BOOKS

Grainger RG, et al. Grainger & Allison’s Diagnostic Radiology: A Textbook of Medical Imaging. 4th ed. Philadelphia: Saunders, 2001.

Katz VL et al. Comprehensive Gynecology. 5th ed. St. Louis: Mosby, 2007.

Mettler, FA. Essentials of Radiology. 2nd ed. Philadelphia: Saunders, 2005.

ORGANIZATIONS

American Cancer Society (ACS), 1599 Clifton Rd., Atlanta, GA 30329. (800) ACS-2345. http://www.cancer.org.

Federal Drug Administration (FDA), 5600 Fishers Ln., Rockville, MD 20857. (800) 532-4440. http://www.fda.gov.

National Cancer Institute (NCI) and Cancer Information Ser vice (CIS), Office of Cancer Communications, Bldg. 31, Room 10A16, Bethesda, MD 20892. (800) 4-CANCER (800) 422-6237. Fax: (800) 624-2511 or (301) 402-5874.<cancermail@cips.nci.nih.gov>. <http://cancernet.nci.nih.gov.>

Lorraine K. Ehresman

Lee A. Shratter, M.D.

Rosalyn Carson-DeWitt, MD

Mammography

Definition

Mammography is the study of the breast using x rays. The actual test is called a mammogram. It is an x ray of the breast which shows the fatty, fibrous, and glandular tissues. There are two types of mammograms. A screening mammogram is ordered for women who have no problems with their breasts. It consists of two x ray views of each breast: a craniocaudal (from above) and a mediolateral oblique (from the sides). A diagnostic mammogram is for evaluation of abnormalities in either men or women. Additional x rays from other angles, or special coned views of certain areas, are taken.

Purpose

The purpose of screening mammography is breast cancer detection. A screening test, by definition, is used for patients without any signs or symptoms, in order to detect disease as early as possible. Many studies have shown that having regular mammograms increases a woman's chances of finding breast cancer in an early stage, when it is more likely to be curable. It has been estimated that a mammogram may find a cancer as much as two or three years before it can be felt. The American Cancer Society (ACS) guidelines recommend an annual screening mammogram for every woman of average risk beginning at age 40. Radiologists look specifically for the presence of microcalcifications and other abnormalities that can be associated with malignancy. New digital mammography and computer-aided reporting can automatically enhance and magnify the mammograms for easier finding of these tiny calcifications.

The highest risk factor for developing cancer is age. Some women are at an increased risk for developing breast cancer, such as those with a positive family history of the disease. Beginning screening mammography at a younger age may be recommended for these women.

Diagnostic mammography is used to evaluate an existing problem, such as a lump, discharge from the nipple, or unusual tenderness in one area. It is also done to evaluate further abnormalities that have been seen on screening mammograms. The radiologist normally views the films immediately and may ask for additional views such as a magnification view of one specific area. Additional studies such as an ultrasound of the breast may be performed as well to determine if the lesion is cystic or solid. Breast-specific positron emission tomography (PET) scans as well as an MRI (magnetic resonance imaging ) may be ordered to further evaluate a tumor, but mammography is still the first choice in detecting small tumors on a screening basis.

Description

A mammogram may be offered in a variety of settings. Hospitals, outpatient clinics, physician's offices, or other facilities may have mammography equipment. In the United States only places certified by the Food and Drug Administration (FDA) are legally permitted to perform, interpret, or develop mammograms. Mammograms are taken with dedicated machines using high frequency generators, low kvp, molybdenum targets and specialized x ray beam filtration. Sensitive high contrast film and screen combinations along with prolonged developing enable the visualization of minute breast detail.

In addition to the usual paperwork, a woman will be asked to fill out a questionnaire asking for information on her current medical history. Beyond her personal and family history of cancer, details about menstruation, previous breast surgeries, child bearing, birth control, and hormone replacement therapy are recorded. Information about breast self-examination (BSE) and other breast health issues are usually available at no charge.

At some centers, a technologist may perform a physical examination of the breasts before the mammogram. Whether or not this is done, it is essential for the technologist to record any lumps, nipple discharge, breast pain or other concerns of the patient. All visible scars, tattoos and nipple alterations must be carefully noted as well.

Clothing from the waist up is removed, along with necklaces and dangling earrings. A hospital gown or similar covering is put on. A small self-adhesive metal marker may be placed on each nipple by the x ray technologist. This allows the nipple to be viewed as a reference point on the film for concise tumor location and easier centering for additional views.

Patients are positioned for mammograms differently, depending on the type of mammogram being performed:

• Craniocaudal position (CC): The woman stands or sits facing the mammogram machine. One breast is exposed and raised to a level position while the height of the cassette holder is adjusted to the same level. The breast is placed mid-film with the nipple in profile and the head turned away from the side being x rayed. The shoulder is relaxed and pulled slightly backward while the breast is pulled as far forward as possible. The technologist holds the breast in place and slowly lowers the compression with a foot pedal. The breast is compressed between the film holder and a rectangle of plastic (called a paddle). The breast is compressed until the skin is taut and the breast tissue firm when touched on the lateral side. The exposure is taken immediately and the compression released. Good compression can be uncomfortable, but it is very necessary. Compression reduces the thickness of the breast, creates a uniform density and separates overlying tissues. This allows for a detailed image with a lower exposure time and decreased radiation dose to the patient. The same view is repeated on the opposite breast.
• Mediolateral oblique position (MLO): The woman is positioned with her side towards the mammography unit. The film holder is angled parallel to the pectoral muscle, anywhere from 30 to 60 degrees depending on the size and height of the patient. The taller and thinner the patient the higher the angle. The height of the machine is level with the axilla (armpit). The arm is placed at the top of the cassette holder with a corner touching the armpit. The breast is lifted forward and upward and compression is applied until the breast is held firmly in place by the paddle. The nipple should be in profile and the opposite breast held away if necessary by the patient. This procedure is repeated for the other breast. A total of four x rays, two of each breast, are taken for a screening mammogram. Additional x rays, using special paddles, different breast positions, or other techniques may be taken for a diagnostic mammogram.

The mammogram may be seen and interpreted by a radiologist right away, or it may not be reviewed until later. If there is any questionable area or abnormality, extra x rays may be recommended. These may be taken during the same appointment. More commonly, especially for screening mammograms, the woman is called back on another day for these additional films.

A screening mammogram usually takes approximately 15 to 30 minutes. A woman having a diagnostic mammogram can expect to spend up to an hour for the procedure.

The cost of mammography varies widely. Many mammography facilities accept "self referral." This means women can schedule themselves without a physician's referral. However, some insurance policies do require a doctor's prescription to ensure payment. Medicare will pay for annual screening mammograms for all women over age 39.

Preparation

The compression or squeezing of the breast necessary for a mammogram is a concern of many women. Mammograms should be scheduled when a woman's breasts are least likely to be tender. One to two weeks after the first day of the menstrual period is usually best, as the breasts may be tender during a menstrual period. Some women with sensitive breasts also find that stopping or decreasing caffeine intake from coffee, tea, colas, and chocolate for a week or two before the examination decreases any discomfort. Women receiving hormone therapy may also have sensitive breasts. Over-the-counter pain relievers are recommended an hour before the mammogram appointment when pain is a significant problem.

Women should not put deodorant, powder, or lotion on their upper body on the day the mammogram is performed. Particles from these products can get on the breast or film holder and may show up as abnormalities on the mammogram. Most facilities will have special wipes available for those patients who need to wash before the mammogram.

Aftercare

No special aftercare is required.

Risks

The risk of radiation exposure from a mammogram is considered minimal and not significant. Experts are unanimous that any negligible risk is by far outweighed by the potential benefits of mammography. Patients who have breast implants must be x rayed with caution and compression is minimally applied so that the sac is not ruptured. Special techniques and positioning skills must be learned before a technologist can x ray a patient with breast implants.

Some breast cancers do not show up on mammograms, or "hide" in dense breast tissue. A normal (or negative) study is not a guarantee that a woman is cancer-free. The false-negative rate is estimated to be 15–20%, higher in younger women and women with dense breasts.

False positive readings are also possible. Breast biopsies may be recommended on the basis of a mammogram, and find no cancer. It is estimated that 75–80% of all breast biopsies resulted in benign (no cancer present) findings. This is considered an acceptable rate, because recommending fewer biopsies would result in too many missed cancers.

Normal results

A mammography report describes details about the x ray appearance of the breasts. It also rates the mammogram according to standardized categories, as part of the Breast Imaging Reporting and Data System (BIRADS) created by the American College of Radiology (ACR). A normal mammogram may be rated as BIRADS 1 or negative, which means no abnormalities were seen. A normal mammogram may also be rated as BIRADS 2 or benign findings. This means there are one or more abnormalities but they are clearly benign (not cancerous), or variations of normal. Some kinds of calcifications, enlarged lymph nodes or obvious cysts might generate a BIRADS 2 rating.

Many mammograms are considered borderline or indeterminate in their findings. BIRADS 3 means either additional images are needed, or an abnormality is seen and is probably (but not definitely) benign. A follow-up mammogram within a short interval of six to 12 months is suggested. This helps to ensure that the abnormality is not changing, or is "stable." Only the affected side will be x rayed at this time. Some women are uncomfortable or anxious about waiting, and may want to consult with their doctor about having a biopsy. BIRADS 4 means suspicious for cancer. A biopsy is usually recommended in this case. BIRADS 5 means an abnormality is highly suggestive of cancer. A biopsy or other appropriate action should be taken.

Screening mammograms are not usually recommended for women under age 40 who have no special risk factors and a normal physical breast examination. A mammogram may be useful if a lump or other problem is discovered in a woman aged 30–40. Below age 30, breasts tend to be "radiographically dense," which means the breasts contain a large amount of glandular tissue which is difficult to image in fine detail. Mammograms for this age group are controversial. An ultrasound of the breasts is usually done instead.

Patient education

The mammography technologist must be empathetic to the patient's modesty and anxiety. He or she must explain that compression is necessary to improve the quality of the image but does not harm the breasts. Patients may be very anxious when additional films are requested. Explaining that an extra view gives the radiologist more information will help to ease the patient's tension. One in eight women in North America will develop breast cancer. Educating the public on monthly breast self-examinations and yearly mammograms will help in achieving an early diagnosis and therefore a better cure.

Resources

periodicals

Carmen, Ricard, R. T. R. Mammography: Techniques and Difficulties. O.T.R.Q., 1999.

Gagnon, Gilbert. Radioprotection in Mammography. O.T.R.Q., 1999.

Ouimet, Guylaine, R. T. R. Mammography: Quality Control. O.T.R.Q., 1999.

organizations

American Cancer Society (ACS), 1599 Clifton Rd., Atlanta, GA 30329. (800) ACS-2345. <http://www.cancer.org>.

Federal Drug Administration (FDA), 5600 Fishers Ln., Rockville, MD 20857. (800) 532-4440. <http://www.fda.gov>.

National Cancer Institute (NCI) and Cancer Information Service (CIS), Office of Cancer Communications, Bldg. 31, Room 10A16, Bethesda, MD 20892. (800) 4-CANCER (800) 422-6237. Fax: (800) 624-2511 or (301) 402-5874. <cancermail@cips.nci.nih.gov>. <http://cancernet.nci.nih.gov>.

Lorraine K. Ehresman
Lee A. Shratter, M.D.

MAMMOGRAPHY

A mammogram is an X-ray examination of the breast, performed for screening or diagnostic purposes. A screening mammogram is used to detect breast cancer before it is clinically apparent. Two views of the breast tissue are taken: a mediolateral (MLO) view and a craniocaudal (CC) view. A diagnostic mammogram is utilized to evaluate abnormalities seen on a screening mammogram or to further characterize abnormalities on physical examination.

Screening mammography has been shown to decrease breast cancer mortality, particularly for women 40 to 50 years of age and older. The first randomized, controlled trial to evaluate the benefit of mammogram and clinical breast-exam screening was the HIP (Health Insurance Plan) study, initiated in 1963. Approximately 62,000 women between 40 and 64 years of age were assigned at random to either a mammography and clinical breast exam group for four years or to a control group. After ten years of follow-up, the study group had a 30 percent lower mortality from breast cancer in comparison to the control group.

Further randomized controlled trials confirmed the efficacy of screening mammography in decreasing breast cancer mortality. A meta-analysis of nine randomized controlled trials and four case-control studies was reported in 1995. Women aged 50 to 74 who received mammographic screening had a decreased relative risk for breast cancer mortality of 0.74 (95% CI [confidence interval],0.66–0.83) in comparison to women who did not receive mammographic screening. No reduction in breast cancer mortality with mammographic screening was seen in women aged 40 to 49, after 7 to 9 years of follow-up. With a longer duration of follow-up of 10 to 12 years, there was a 17 percent decrease in breast cancer mortality among women aged 40 to 49 who received screening mammography.

A meta-analyses of eight randomized trials of screening mammography in women aged 40 to 49 was published in 1997. This meta-analysis demonstrated an 18 percent mortality reduction in women aged 40 to 49 who received screening mammography, after 10.5 to 18 years of follow-up.

Based on these results, it is clear that women 50 years old and older benefit from yearly screening mammography in order to decrease their risk of dying from breast cancer; however, there is controversy regarding the utility of screening mammography in women aged 40 to 49. An attempt at resolving this controversy was made at the National Institute of Health Consensus meeting in January 1997, but a consensus could not be reached. Therefore the meeting resulted in two different reports regarding screening mammography in women aged 40 to 49. The majority concluded that screening mammogram was not universally warranted in this age group. A minority report, however, supported the recommendation for screening mammography based on the survival benefit seen at 10 years and longer after screening is initiated. The American Cancer Society supports this recommendation, recommending an annual mammogram for women aged 40 and older.

Another area of controversy is the upper age limit at which to stop performing screening mammography. There is no data from randomized trials regarding the benefits of screening mammography in women older than 75 because of the lack of enrollment of elderly women. This area deserves further study, given that age is the single greatest risk factor for breast cancer and approximately half of all breast cancers occur in women over the age of 65. The American Cancer Society and the National Cancer Institute put no upper age cut-off for screening mammography. The American Geriatric Society has published a position statement regarding breast cancer screening in older women, recommending no upper age limit for breast cancer screening for women with an estimated life expectancy of greater than four years (2000).

Ultimately, the decision regarding screening mammography is up to the patient. Therefore, it is important for a clinician to discuss the benefits and risks of mammographic screening with each individual. The risks of mammographic screening include the risk of a false positive exam, which can lead to further testing, cost, and patient anxiety. Younger women have a higher rate of false positive and false negative exams, a consequence of the exam being less sensitive and specific in this age group. In addition, there is an exceedingly small risk of breast cancer due to radiation exposure from the mammogram. Statistical models indicate that 8 out of 100,000 women who underwent an annual mammogram for 10 years beginning at age 40 develop breast cancer and die from the disease during their lifetime. Women with DNA repair mechanism impairment may be at greater risk.

Clifford Hudis

Arti Hurria

(see also: Breast Cancer; Breast Cancer Screening; Breast Self-Examination; Clinical Breast Examination; Tamoxifen )

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Armstrong, K.; Eisen, A.; and Weber, B. (2000). "Assessing the Risk of Breast Cancer." New England Journal of Medicine 342(8):564–571.

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—— (1982). "Ten- to Fourteen–Year Effect of Screening on Breast Cancer Mortality." Journal of the National Cancer Institute 69:349–355.